6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

A box contains 10 bulbs,of which just three are defective. If a random sample of five bulbs is drawn, find the probability that the sample contains exactly one defective bulb.

A) 5/12	B) 7/12
C) 3/14	D) 1/12

Answer & Explanation Answer: A) 5/12

Explanation:

Total number of elementary events = $10 C_{5}$

Number of ways of selecting exactly one defective bulb out of 3 and 4 non-defective out of 7 is $3 C_{1} * 7 C_{4}$

So,required probability = $3 C_{1} * 7 C_{4}$ / $10 C_{5}$ = 5/12.

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Filed Under: Probability

66 34639

Q:

Find the odd word/letters/number pair from the given alternatives.

(A) AE (B) CG (C) JN (D) MO

A) A	B) B
C) C	D) D

Answer & Explanation Answer: D) D

Explanation:

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Filed Under: Odd Man Out
Exam Prep: Bank Exams

1 34429

Q:

The ratio between the speeds of two trains is 7: 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is ?

A) 83.5 km/hr	B) 84.5 km/hr
C) 86.5 km/hr	D) 87.5 km/hr

Answer & Explanation Answer: D) 87.5 km/hr

Explanation:

Let the speeds of two trains be 7X and 8X km/hr.

8x = 400/4

=> x= 12.5 km/hrX=4004=>X=12.5Km/hr

So speed of first train is 12.5*7 = 87.5 km/hr

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Filed Under: Time and Distance

63 34394

Q:

Find the odd word/letters/number from the given alternatives.

(A) Barbarous

(B) Uncivilized

(C) Gentle

(D) Wild

A) A	B) B
C) C	D) D

Answer & Explanation Answer: C) C

Explanation:

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Filed Under: Odd Man Out
Exam Prep: Bank Exams

0 34388

Q:

The diluted wine contains only 8 liters of wine and the rest is water. A new mixture whose concentration is 30%, is to be formed by replacing wine. How many liters of mixture shall be replaced with pure wine if there was initially 32 liters of water in the mixture ?

A) 4	B) 5
C) 8	D) None of these

Answer & Explanation Answer: B) 5

Explanation:

Wine Water

8L 32L

1 : 4

20 % 80% (original ratio)

30 % 70% (required ratio)

In ths case, the percentage of water being reduced when the mixture is being replaced with wine.

so the ratio of left quantity to the initial quantity is 7:8

Therefore , $\frac{7}{8} = [1 - \frac{K}{40}]$

=> K = 5 Lit

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Filed Under: Alligation or Mixture
Exam Prep: CAT , Bank Exams
Job Role: Bank PO , Bank Clerk

94 34380

Q:

The diagonal of a rectangle is $\sqrt{41}$ cm and its area is 20 sq. cm. The perimeter of the rectangle must be:

A) 18	B) 28
C) 38	D) 48

Answer & Explanation Answer: A) 18

Explanation:

$\sqrt{(l^{2} + b^{2})} = \sqrt{41}$ (or) $l^{2} + b^{2} = 41$

Also, $l b = 20$

${(l + b)}^{2} = l^{2 +} b^{2} + 2 l b$ = 41 + 40 = 81

(l + b) = 9.

Perimeter = 2(l + b) = 18 cm.

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Filed Under: Area
Exam Prep: CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

129 34366

Q:

The average age of 36 students in a group is 14 years. When teacher's age is included to it, the average increases by one. What is the teacher's age in years ?

A) 35 years	B) 45 years
C) 51 years	D) 54 years

Answer & Explanation Answer: C) 51 years

Explanation:

Age of the teacher = (37 * 15 - 36 * 14) years = 51 years.

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Filed Under: Average

28 34258

Q:

Out of 9 persons, 8 persons spent Rs. 30 each for their meals. The ninth one spent Rs. 20 more than the average expenditure of all the nine. The total money spent by all of them was :

A) Rs. 292.50	B) Rs. 297.50
C) Rs. 298	D) Rs. 298.50

Answer & Explanation Answer: A) Rs. 292.50

Explanation:

Let the average expenditure be Rs. x Then,

9x=[(8*30)+(x+20)]<=>9x =x+260 <=> x =32.50

Total money spent = 9x = Rs. (9 x 32.5O) = Rs 292. 50

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Filed Under: Average

95 34226

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