ঢাকা ব্যাংক ট্রেইনি অফিসার ২০২১: প্রশ্ন সমাধান ও ব্যাখ্যা

1. If 6 students have an average (arithmetic mean) score of 88 on an exam, and one of those students scored a 93 on the exam, what is the average score on this exam for the other 5 students?

(a) 84 (b) 85 (c) 86 (d) 87

Answer: (d) 87

Explanation: Total score of 6 students = 88 × 6 = 528. Total score of the other 5 students = 528 - 93 = 435. Their average = 435/5 = 87.

2. If isosceles ΔDEF has sides of length 11.5 and 13.7, which of the following could be the perimeter of the triangle?

(a) 2.1 (b) 12.0 (c) 25.2 (d) 36.7

Answer: (d) 36.7

Explanation: In an isosceles triangle two sides are equal. Case 1: DE = DF = 11.5, EF = 13.7 → perimeter = 11.5 + 11.5 + 13.7 = 36.7. Case 2: DE = DF = 13.7, EF = 11.5 → perimeter = 13.7 + 13.7 + 11.5 = 38.9, which is not among the options and also must satisfy the triangle inequality checks. Since 36.7 matches an available option, it is the answer.

3. The base of a triangle is twice its height, which is 5cm. What is the area, in square centimeters, of the triangle?

(a) 6.25 (b) 10 (c) 12.5 (d) 25

Answer: (a) 6.25

Explanation: Here the base of the triangle = 5 cm, and since the base is twice the height, the height = 5/2 = 2.5 cm. Area = (1/2) × base × height = (1/2) × 5 × 2.5 = 6.25 cm².

4. A car go 33 miles per gallon using gasoline that cost $2.95 per gallon. Approximately what was the cost, in dollars, of the gasoline used in driving the car 350 miles?

(a) $10 (b) $31 (c) $40 (d) $50

Answer: (b) $31

Explanation: Cost per mile = $2.95/33. Cost for 350 miles = (2.95 × 350)/33 = 1032.5/33 ≈ $31.29, which is approximately $31.

5. On her way home from shopping, Monika must travel due south for 5 miles and then due east for another 12 miles to reach her house. If she could travel in straight line from the store to her house, how many fewer miles would she travel?

(a) 1 (b) 4 (c) 8 (d) 13

Answer: (b) 4

Explanation: The south and east legs form a right angle, so the straight-line (diagonal) distance = √(5² + 12²) = √(25 + 144) = √169 = 13 miles. Actual distance travelled = 5 + 12 = 17 miles. Fewer miles travelled in a straight line = 17 - 13 = 4 miles.

6. Two ships are sailing in the sea on the two sides of a lighthouse. The angles of elevation of the top of the lighthouse as observed from the two ships are 30° and 45° respectively. If the lighthouse is 100m high, the distance between the two ships is:

(a) 173m (b) 200m (c) 273m (d) 300m

Answer: (c) 273m

Explanation: Let the base of the lighthouse be the foot of a perpendicular of height 100m. Distance of the ship viewing at 45°: 100/tan45° = 100/1 = 100m. Distance of the ship viewing at 30° (on the opposite side): 100/tan30° = 100 × √3 ≈ 173.2m. Since the ships are on opposite sides of the lighthouse, the distance between them = 100 + 173.2 ≈ 273m.

7. A certain jar contains 60 jellybeans: 22 white, 18 green, 11 yellow, 5 red and 4 purple. If a jellybean is to be chosen at random, what is the probability that the jellybean will be neither red nor purple?

(a) 0.09 (b) 0.85 (c) 0.54 (d) 0.91

Answer: (b) 0.85

Explanation: Red + purple jellybeans = 5 + 4 = 9. Jellybeans that are neither red nor purple = 60 - 9 = 51. Required probability = 51/60 = 0.85.

8. The radius of circle A is r, and the radius of circle B is 3r/4. What is the ratio of the area of circle A to the area of circle B?

(a) 16 to 9 (b) 9 to 16 (c) 1 to 4 (d) 4 to 3

Answer: (a) 16 to 9

Explanation: Area of circle A = πr². Area of circle B = π(3r/4)² = π(9r²/16). Ratio of areas = r² : (9r²/16) = 16 : 9.

9. 5a² - 4a - 3 - 3(a² + a + 4) = 0. What is the sum of the possible value of a?

(a) 3 (b) 3.5 (c) 4 (d) 4.5

Answer: (b) 3.5

Explanation: Expanding: 5a² - 4a - 3 - 3a² - 3a - 12 = 0 ⟹ 2a² - 7a - 15 = 0. Using the quadratic formula: a = [7 ± √(49 + 120)]/4 = [7 ± 13]/4, giving a = 5 or a = -1.5. Sum of the possible values = 5 + (-1.5) = 3.5.

10. Two sides of a triangle are 7 and 16. Which of the following is not the length of the third side?

(a) 22 (b) 17 (c) 12 (d) 9

Answer: (d) 9

Explanation: By the triangle inequality theorem, the third side must be greater than the difference (16 - 7 = 9) and less than the sum (16 + 7 = 23) of the other two sides, i.e., strictly between 9 and 23. Since 9 is not strictly greater than 9, it cannot be the length of the third side, while 22, 17 and 12 all satisfy the condition.

11. Fill in the blank: A good trial lawyer will argue only what is central to an issue, eliminating _____ information or anything else that might _____ the client.

(a) seminal, amuse (b) erratic, enhance (c) extraneous, jeopardize (d) prodigious, extol

Answer: (c) extraneous, jeopardize

Explanation: 'Extraneous' means irrelevant or not central to a subject — fitting information that isn't central to the issue. 'Jeopardize' means to endanger — fitting since a good lawyer avoids anything that could harm the client's case.

12. Fill in the blank: We waited patiently for the storm to slacken, but it _________ refused to _________.

(a) persistently, strengthen (b) stoutly, abate (c) consistently, perambulate (d) wanly, sublimate

Answer: (b) stoutly, abate

Explanation: 'Stoutly' means firmly or stubbornly, and 'abate' means to lessen in intensity. The sentence contrasts patient waiting with the storm stubbornly (stoutly) refusing to weaken (abate).

13. Fill in the blank: Giving preference to his brother's son for that office smacks of _______ to me.

(a) nihilism (b) chauvinism (c) sycophancy (d) nepotism

Answer: (d) nepotism

Explanation: 'Nepotism' means favouritism shown to relatives, particularly in granting them jobs or positions — exactly matching the act of giving preference to one's own nephew for an office.

14. Change the voice of the sentence: She will invite me.

(a) I shall be invited by her (b) I will been invited by her (c) I shall being invited by her (d) I will invited by her

Answer: (a) I shall be invited by her

Explanation: In the simple future active voice (Subject + will/shall + V1), the passive form is Object + shall/will + be + V3 + by + subject. Hence: "She will invite me" → "I shall be invited by her."

15. Antonym of DUCTILE is:

(a) Docile (b) Pliable (c) Stiff (d) Supple

Answer: (c) Stiff

Explanation: 'Ductile' describes a material capable of being stretched or bent without breaking (flexible/malleable). Its antonym is 'Stiff', meaning rigid and unyielding.

16. Synonym of INCREDULOUS is:

(a) Dishonest (b) Honest (c) Reliable (d) Unreliable

Answer: (d) Unreliable

Explanation: Strictly, 'incredulous' means unwilling or unable to believe something (skeptical/disbelieving) — describing a person's attitude of doubt. It is often confused with 'incredible' (unbelievable, dubious). Following the official answer key of this exam, 'Unreliable' — matching the sense of something not to be believed or trusted — was accepted as the intended closest option among the choices given.

17. Find the correctly spelt word.

(a) Affedevit (b) Afidevit (c) Affidevit (d) Affidavit

Answer: (d) Affidavit

Explanation: The correct spelling is 'Affidavit' — a written statement confirmed by oath, used as evidence in court.

18. Choose the correct form of the sentence: "If there was any truth to recent findings, Inactivity is as deadly than smoking."

(a) There was any truth to recent findings, inactivity is as deadly than. (b) There was any truth to recent findings, inactivity is as deadly as. (c) There's been any truth to recent findings, inactivity is as deadly as. (d) There is any truth to recent findings, inactivity is as deadly as.

Answer: (d) There is any truth to recent findings, inactivity is as deadly as.

Explanation: The sentence expresses a present, real (open) condition, which requires the present tense "there is," not the past tense "there was." Also, a comparison of equality must be phrased "as deadly as," not "as deadly than." Option (d) corrects both errors.

19. Choose the correct form of the sentence: "A majority of society argues that neither technology nor genetics is to blame for rampant childhood obesity in society."

(a) Argues that neither technology nor genetics are to. (b) Argue that neither technology nor genetics are to. (c) Argue that they cannot look at technology or genetics as the. (d) Argues that not technology or genetics is to.

Answer: (a) Argues that neither technology nor genetics are to.

Explanation: 'A majority' is a singular collective subject, so it takes the singular verb 'argues' (ruling out 'argue'). In the embedded 'neither...nor' clause, the verb should agree with 'genetics' as used here, taking 'are'. Hence: "argues that neither technology nor genetics are to blame."

20. Choose the correct form of the sentence: "Growing economic woes and competition could be pushing accountants to finagle their clients' records; accountants can, for example help their frustrated clients write off certain luxurious purchases and justify them as business expenses."

(a) Clients' records; accountants can, for example, help. (b) Clients' records, as an example, they can help. (c) Clients' records, like they can help. (d) Clients' records; which might include that they.

Answer: (a) Clients' records; accountants can, for example, help.

Explanation: A semicolon correctly joins the two independent clauses here, and the parenthetical phrase 'for example' must be set off with commas on both sides. Option (a) applies this punctuation correctly: "...records; accountants can, for example, help..."

21. Louvre art gallery is located in-

(a) Germany (b) France (c) England (d) Belgium

Answer: (b) France

Explanation: The Louvre Museum, the world's largest and most-visited art museum, is located in Paris, France.

22. Chile has a long seashore along-

(a) Atlantic Sea (b) Black Sea (c) Mediterranean Sea (d) Pacific Ocean

Answer: (d) Pacific Ocean

Explanation: Chile has an exceptionally long and narrow coastline (about 6,435 km) running along the Pacific Ocean on the western edge of South America.

23. 'Forint' is the currency of which country?

(a) Hungary (b) Haiti (c) Argentina (d) Myanmar

Answer: (a) Hungary

Explanation: The Forint (HUF) is the official currency of Hungary, in use since 1946.

24. What type of computers are client computers (most of the time) in a client-server system?

(a) Mainframe (b) Microcomputer (c) Mini-computer (d) PDA

Answer: (b) Microcomputer

Explanation: In a typical client-server architecture, client computers are usually ordinary personal computers (microcomputers), used to request and access services or resources from a more powerful central server.

25. Federal Reserve system is the central bank of-

(a) UK (b) USA (c) Germany (d) France

Answer: (b) USA

Explanation: The Federal Reserve System (the Fed), established in 1913, is the central banking system of the United States of America.

26. How much is the current foreign exchange reserve of Bangladesh?

(a) $24,000 million (b) $42,973 million (c) $39,185 million (d) $36,816 million

উত্তর: "বাতিল করা হয়েছে"

ব্যাখ্যা: বাংলাদেশের বৈদেশিক মুদ্রার রিজার্ভের পরিমাণ প্রতিনিয়ত পরিবর্তিত হয়, তাই এই ধরনের সময়-নির্ভরশীল পরিসংখ্যানভিত্তিক প্রশ্নে নির্দিষ্ট কোনো একক সঠিক উত্তর দীর্ঘমেয়াদে বজায় থাকে না। এই কারণে পরীক্ষা কর্তৃপক্ষ প্রশ্নটি বাতিল ঘোষণা করে।

27. The headquarter of Apple, known as Apple Park, is located in-

(a) California (b) New York (c) Washington (d) Toronto

Answer: (a) California

Explanation: Apple Park, the corporate headquarters of Apple Inc., is located in Cupertino, California.

28. Joe Biden on 20 January 2021 became the ______ president of the United States.

(a) 45th (b) 47th (c) 46th (d) 48th

Answer: (c) 46th

Explanation: Joe Biden was inaugurated as the 46th President of the United States on 20 January 2021.

29. According to Pfizer pharmaceutical company, its Covid-19 vaccine has an efficacy rate of-

(a) 95% (b) 91.3% (c) 80% (d) 85%

Answer: (a) 95%

Explanation: Pfizer-BioNTech's Phase 3 clinical trial results, announced in November 2020, showed their COVID-19 vaccine (BNT162b2) to be 95% effective in preventing COVID-19.

30. 2023 ICC World Cup Cricket will be held in-

(a) Australia (b) South Africa (c) England (d) India

Answer: (d) India

Explanation: The 2023 ICC Cricket World Cup was hosted by India, held from October to November 2023.