6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

What is the probability of getting at least one six in a single throw of three unbiased dice?

A) 1/36	B) 91/256
C) 13/256	D) 43/256

Answer & Explanation Answer: B) 91/256

Explanation:

Find the number of cases in which none of the digits show a '6'.

i.e. all three dice show a number other than '6', 5×5×5=125 cases.

Total possible outcomes when three dice are thrown = 216.

The number of outcomes in which at least one die shows a '6' = Total possible outcomes when three dice are thrown - Number of outcomes in which none of them show '6'.

=216−125=91

The required probability = 91/256

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Filed Under: Probability

27 20022

Q:

A boatman can row 3 km against the stream in 20 minutes and return in 18 minutes. Find the rate of current ?

A) 1/3 kmph	B) 2/3 kmph
C) 1/4 kmph	D) 1/2 kmph

Answer & Explanation Answer: D) 1/2 kmph

Explanation:

Speed in upstream = Distance / Time = 3 x 60/20 = 9 km/hr.

Speed in downstream = 3 x 60/18 = 10 km/hr

Rate of current = (10-9)/2 = 1/2 km/hr.

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Filed Under: Boats and Streams
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Bank Clerk , Bank PO

32 20015

Q:

The present average age of a family of five members is 26 years. If the present age of the youngest member in the family is ten years, then what was the average age of the family at the time of the birth of the youngest member ? (Assume no death occurred in the family since the birth of the youngest)

A) 19 years	B) 16 years
C) 18 years	D) 20 years

Answer & Explanation Answer: D) 20 years

Explanation:

Present total age of the members = 26(5) = 130 years.

Present age of the youngest member = 10 years

Present total age of the remaining four members = 130 -10 = 120 years

Their average age at the time of the birth of the youngest member = $\frac{[120 - (4 \times 10)]}{4}$ = 30 - 10 = 20 years.

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Filed Under: Problems on Ages
Exam Prep: GATE , CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

19 20007

Q:

The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is :

A) 25	B) 35
C) 45	D) 55

Answer & Explanation Answer: B) 35

Explanation:

Excluded number = (27 x 5) - (25 x 4) = 135 - 100 = 35.

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Filed Under: Average

31 19953

Q:

The ratios of areas of two squares, one having its diagonal double than the other is

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

Answer & Explanation Answer: D) 4:1

Explanation:

ratio = $\frac{(1 / 2) \times {(2 d)}^{2}}{\frac{1}{2} d^{2}} = 4 : 1$

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

49 19945

Q:

A tailor has 37.5 metres of cloth and he has to make 8 pieces out of a metre of cloth. How many pieces can he make out this cloth ?

A) 300	B) 360
C) 400	D) 450

Answer & Explanation Answer: A) 300

Explanation:

Length of each piece = (1/8) m = 0.125 m

Required no of pieces = (37.5/0.125) = (375 * 100) / 125 = 300.

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Filed Under: Decimal Fractions

36 19906

Q:

Three friends, P, Q and R started a partnership business investing money in the ratio of 5 : 4 : 2 respectively for a period of 3 years. What is the amount received by P as his share in the total profit ?

a. Total amount invested in the business in Rs. 22,000.

b. Profit earned at the end of 3 years is 3/8 of the total investment.

c. The average amount of profit earned per year is Rs. 2750.

A) Only c is sufficient	B) Both a & b are sufficient
C) Both A & B gives result	D) None

Answer & Explanation Answer: C) Both A & B gives result

Explanation:

a and b give, profit after 3 years = Rs.(3/8 x 22000) = Rs.8250.

From c also, profit after 3 years = Rs. (2750 x 3) = Rs. 8250.

∴ P's share = Rs.(8250 x 5/11) = Rs. 3750.

Thus, (either C is redundant) or (a and b are redundant).

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

5 19888

Q:

A 3 by 4 rectangle is inscribed in circle. What is the circumference of the circle?

A) 2.5π	B) 3π
C) 5π	D) 4π

Answer & Explanation Answer: C) 5π

Explanation:

Draw the diagram. The diagonal of the rectangle is the diameter of the circle. The diagonal is the hypotenuse of a 3,4,5 triangle and is therefore, 5.

Quantitative Aptitude - Arithmetic Ability Questions

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