6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

The H.C.F and L.C.M of two numbers are 84 and 21 respectively. If the ratio of the two numbers is 1 : 4 , then the larger of the two numbers is

A) 12	B) 48
C) 84	D) 108

Answer & Explanation Answer: C) 84

Explanation:

Let the numbers be x and 4x. Then, $x \times 4 x = 84 \times 21 \Leftrightarrow x^{2} = \frac{84 \times 21}{4} \Leftrightarrow x = 21$

Hence Larger Number = 4x = 84

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Filed Under: HCF and LCM

26 24298

Q:

In a college, the ratio of the number of boys to girls is 8 : 5. If there are 160 girls, the total number of students in the college is

A) 100	B) 250
C) 260	D) 416

Answer & Explanation Answer: D) 416

Explanation:

Let the number of boys and girls be 8x and 5x.
Total number of students = 13x = 13 * 32 = 416.

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Filed Under: Ratios and Proportions

97 24287

Q:

The ages of Krish and Vaibhav are in the proportion of 3 : 5. After 9 years, the proportion of their ages will be 3 : 4. Then the current age of Vaibhav is:

A) 10	B) 13
C) 15	D) 18

Answer & Explanation Answer: C) 15

Explanation:

Krish’s age = 3A and Vaibhav’s age = 5A

(3A+9)/(5A+9) = 3/4

=> 4 (3A + 9) = 3 (5A + 9)

=> A = 3

Therefore, Vaibhav’s age = 15 years.

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Filed Under: Problems on Ages

45 24287

Q:

A man invests Rs.5000 for 3 years at 5% p.a. compound interest reckoned yearly. Income tax at the rate of 20% on the interest earned is deducted at the end of each year. Find the amount at the end of the third year

A) Rs.5624.32	B) Rs.5423
C) Rs.5634	D) Rs.5976

Answer & Explanation Answer: A) Rs.5624.32

Explanation:

5% is the rate of interest. 20% of the interest amount is paid as tax.

i.e 80% of the interest amount stays back.

$\therefore$ if we compute the rate of interest as 80% of 5% = 4% p.a., we will get the same value.

The interest accrued for 3 years in compound interest = 3 x simple interest on principal + 3 x interest on simple interest + 1 x interest on interest on interest.

= 3 x (200) + 3 x (8) + 1 x 0.32 =600 + 24 + 0.32 = 624.32

The amount at the end of 3 years = 5000 + 624.32 = 5624.32

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Filed Under: Compound Interest
Exam Prep: Bank Exams
Job Role: Bank PO

26 24276

Q:

A group of workers was put on a job. From the second day onwards, one worker was withdrawn each day. The job was finished when the last worker was withdrawn. Had no worker been withdrawn at any stage, the group would have finished the job in 55% of the time. How many workers were there in the group?

A) 50	B) 40
C) 45	D) 10

Answer & Explanation Answer: D) 10

Explanation:

Let the number of workers be x.

Now, Using work equivalence method,

X + (X-1) + (X-2)+ . . . . + 1 = X *55% of X

=> [X * (X+1)] / 2 = X * (55X/100) [because, Series is in AP. Sum of AP = {No. of terms (first term+ last term)/2} ]

Therefore, X = 10

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Filed Under: Time and Work

63 24271

Q:

Out of 17 applicants 8 boys and 9 girls. Two persons are to be selected for the job. Find the probability that at least one of the selected persons will be a girl.

A) 19/34	B) 5/4
C) 20/34	D) 25/34

Answer & Explanation Answer: D) 25/34

Explanation:

The events of selection of two person is redefined as first is a girl and second is a boy or first is boy and second is a girl or first is a girl and second is a girl.

So the required probability:
= $(\frac{8}{17} * \frac{9}{16}) + (\frac{9}{17} * \frac{8}{16}) + (\frac{8}{17} * \frac{7}{16})$

= $\frac{9}{34} + \frac{9}{34} + \frac{7}{34}$
= $\frac{25}{34}$

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Filed Under: Probability

21 24249

Q:

Consider the following grouped frequency distribution:

x f

0-10 8

10-20 12

20-30 10

30-40 p

40-50 9

If the mean of the above data is 25.2, then what is the value of p?

A) 9	B) 10
C) 11	D) 12

Answer & Explanation Answer: C) 11

Explanation:

Mean = (sum of fixi/ (sum of f) = (8*5 + 12*15 + 10*25 + P*35 +9*45) / (8+12+10+P+9) = 25.2

(875 + 35P)/(39+P) = 25.2

P = 11

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Filed Under: Average
Exam Prep: Bank Exams

0 24216

Q:

What is the least number consisting of five digits that is exactly divisible by 12, 18, 20 and 25?

A) 10800	B) 11250
C) 10000	D) 10680

Quantitative Aptitude - Arithmetic Ability Questions

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