6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

Two brother X and Y appeared for an exam. The probability of selection of X is 1/7 and that of B is 2/9. Find the probability that both of them are selected.

A) 1/63	B) 1/14
C) 2/63	D) 1/9

Answer & Explanation Answer: C) 2/63

Explanation:

Let A be the event that X is selected and B is the event that Y is selected.

P(A) = 1/7, P(B) = 2/9.

Let C be the event that both are selected.

P(C) = P(A) × P(B) as A and B are independent events:

= (1/7) × (2/9) = 2/63

Report Error

View Answer Report Error Discuss

Filed Under: Probability

30 33734

Q:

In a History examination, the average for the entire class was 80 marks. If 10% of the students scored 35 marks and 20% scored 90 marks, what was the average marks of the remaining students of the class ?

A) 25	B) 50
C) 75	D) 100

Answer & Explanation Answer: C) 75

Explanation:

Let the number of students in the class be 100 and let this required average be x.

Then, (10 * 95) + (20 * 90) + (70 * x) = (100 * 80)

=> 70x = 8000 - (950 + 1800) = 5250

=> x = 75.

Report Error

View Answer Report Error Discuss

Filed Under: Percentage

113 33639

Q:

The ratio of the areas of a square and a regular hexagon, both inscribed in a circle is?

A) 4 : 3√3	B) 1 : √3
C) 3√3 : 2	D) 2 : 3

Answer & Explanation Answer: A) 4 : 3√3

Explanation:

Report Error

View Answer Report Error Discuss

Filed Under: Area
Exam Prep: Bank Exams

1 33572

Q:

The ratio of petrol and kerosene in the container is 3:2 when 10 liters of the mixture is taken out and is replaced by the kerosene, the ratio become 2:3. Then total quantity of the mixture in the container is:

A) 25	B) 30
C) 45	D) cannot be determined

Answer & Explanation Answer: B) 30

Explanation:

pool : kerosene

3 : 2(initially)

2 : 3(after replacement)

$\frac{R e m a i n i n g Q u a n t i t y}{I n i t i a l Q u a n t i t y} = (1 - \frac{R e p l a c e d Q u a n t i t y}{T o t a l Q u a n t i t y})$

(for petrol) $\frac{2}{3} = (1 - \frac{10}{k})$

=> K = 30

Therefore the total quantity of the mixture in the container is 30 liters.

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

83 33500

Q:

What is the probability of getting 53 Mondays in a leap year?

A) 1/7	B) 3/7
C) 2/7	D) 1

Answer & Explanation Answer: C) 2/7

Explanation:

1 year = 365 days . A leap year has 366 days

A year has 52 weeks. Hence there will be 52 Sundays for sure.

52 weeks = 52 x 7 = 364days

366 – 364 = 2 days

In a leap year there will be 52 Sundays and 2 days will be left.

These 2 days can be:

1. Sunday, Monday

2. Monday, Tuesday

3. Tuesday, Wednesday

4. Wednesday, Thursday

5. Thursday, Friday

6. Friday, Saturday

7. Saturday, Sunday

Of these total 7 outcomes, the favourable outcomes are 2.

Hence the probability of getting 53 days = 2/7

Report Error

View Answer Report Error Discuss

Filed Under: Probability

148 33463

Q:

Read the data given below and answer the questions based on it.

In the CBSE Board exams last year, 53% passed in Biology, 61% percent passed in English, 60% in Social studies, 24% in Biology and English, 35% in English and social studies, 27% in Biology and social studies and 5% in none.

What is the ratio of percentage of students who passed in Biology and Social Studies but not English in relation to the percentage of students who passed in Social Studies and English but not Biology?

A) 5:7	B) 7:5
C) 4:5	D) 5:4

Answer & Explanation Answer: A) 5:7

Explanation:

Report Error

View Answer Report Error Discuss

Filed Under: Percentage
Exam Prep: Bank Exams

2 33463

Q:

A father left a will of Rs.35 lakhs between his two daughters aged 8.5 and 16 such that they may get equal amounts when each of them reach the age of 21 years. The original amount of Rs.35 lakhs has been instructed to be invested at 10% p.a. simple interest. How much did the elder daughter get at the time of the will?

A) 17.5 lakhs	B) 21 lakhs
C) 15 lakhs	D) 20 lakhs

Answer & Explanation Answer: B) 21 lakhs

Explanation:

Let Rs.x be the amount that the elder daughter got at the time of the will. Therefore, the younger daughter got (3,500,000 - x).

The elder daughter’s money earns interest for (21 - 16) = 5 years @ 10% p.a simple interest.

The younger daughter’s money earns interest for (21 - 8.5) = 12.5 years @ 10% p.a simple interest.

As the sum of money that each of the daughters get when they are 21 is the same,

$x + \frac{5 * 10 * x}{100} = (3, 500, 000 - x) + \frac{12.5 * 10 * (3, 500, 000 - x)}{100}$

$x + \frac{50}{x} = 3, 500, 000 - x + \frac{125}{100} * 3, 500, 000 - \frac{125 x}{100}$

$2 x + \frac{50 x}{100} + \frac{125 x}{100} = 3, 500, 000 * (1 + \frac{5}{4})$

$\frac{200 x + 50 x + 125 x}{100} = \frac{9}{4} * (3, 500, 000)$

=> $x = 2, 100, 000 = 21 l a k h s$

Report Error

View Answer Report Error Discuss

Filed Under: Simple Interest
Exam Prep: GRE

57 33385

Q:

A and B can do a piece of work in 30 days , while B and C can do the same work in 24 days and C and A in 20 days . They all work together for 10 days when B and C leave. How many days more will A take to finish the work?

A) 18 days	B) 24 days
C) 30 days	D) 36 days

Answer & Explanation Answer: A) 18 days

Explanation:

2(A+B+C)'s 1 day work = 1/30 + 1/24 + 1/20 = 1/8

=>(A+B+C)'s 1 day's work= 1/16

work done by A,B and C in 10 days=10/16 = 5/8

Remaining work= 3/8

A's 1 day's work= $(\frac{1}{16} - \frac{1}{24}) = \frac{1}{48}$

Now, 1/48 work is done by A in 1 day.

So, 3/8 work wil be done by A in =48 x (3/8) = 18 days

Report Error

View Answer Report Error Discuss

Filed Under: Time and Work

138 33374

Quantitative Aptitude - Arithmetic Ability Questions

Quick Links