Quantitative Aptitude - Arithmetic Ability Questions

Q:

Find the average of first 50 natural numbers?

A) 25 B) 25.5
C) 26 D) 26.5
 
Answer & Explanation Answer: B) 25.5

Explanation:

We Know that sum of the n natural numbers =n(n+1)2

  

Then sum of 50 natural numbers= 50(51)2= 1250

  

Average of the 50 natural numbers = 125050 = 25.5

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Q:

How much water (in litres) must be added to 80 litres solution of milk and water containing 10% milk, so that it becomes a 5% milk solution?

A) 10 B) 20
C) 40 D) 80
 
Answer & Explanation Answer: D) 80

Explanation:
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Q:

From well shuffled standard pack of 52 playing cards,one card is drawn. What is the probability that it is either a red card or black card?

A) 1/2 B) 3/4
C) 1 D) 1/3
 
Answer & Explanation Answer: C) 1

Explanation:

P(red cards)=26/52

P(black cards)=26/52

P(red or black cards)=26/52+26/52=1

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Q:

If 3A = 2B = 4C; then what is A : B : C?

A) 3 : 2 : 4 B) 6 : 4 : 3
C) 4 : 6 : 3 D) 2 : 3 : 4
 
Answer & Explanation Answer: C) 4 : 6 : 3

Explanation:
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Q:

In a bag, there are 8 red, 7 blue and 6 green flowers. One of the flower is picked up randomly. What is the probability that it is neither red nor green ?

A) 13

B)821

C)621

D)2021

A) Option A B) Option B
C) Option C D) Option D
 
Answer & Explanation Answer: A) Option A

Explanation:

Total number of flowers = (8+7+6) = 21.

 

Let E = event that the flower drawn is neither red nor green. 

= event taht the flower drawn is blue. 

 

--> n(E)= 7 

--> P(E)=  721=13 

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Q:

One card is drawn from deck of 52 cards, each of the 52 cards being equally likely to be drawn. Find the probability that the ball drawn is red.

A) 1/3 B) 1/2
C) 1/4 D) 1/6
 
Answer & Explanation Answer: B) 1/2

Explanation:

Total number of elementary events = 52

 

There are 26 red cards,out of which one red card can be drawn in 26C1 ways =26.

 

So,required probability = 26/52 = 1/2

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Q:

Jar A has 36 litres of mixture of milk and water in the respective ratio of 5 : 4. Jar B which had 20 litres of mixture of milk and water, was emptied into jar A, and as a result in jar A, the respective ratio of milk and water becomes 5: 3. What was the quantity of water in jar B?

A) 5 lit B) 3 lit
C) 8 lit D) 2 lit
 
Answer & Explanation Answer: A) 5 lit

Explanation:

Jar A has 36 litres of mixture of milk and water in the respective ratio of 5 : 4 => Quantity of milk in Jar A = 5/9 x 36 = 20 litres Quantity of water in Jar A = 36 - 20 = 16 litres Let quantity of water in Jar B = x litres => Quantity of milk in Jar B = (20 - x) litres Acc. to ques, =>[20 + (20-x)]/(16+x) = 5/3 => 120−3x = 80+5x => 5x +3x = 120−80 => 8x = 40 => 5 litres.

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Q:

Calculate the effective interest rate compounded quarterly of a 13% annual rate.

A) 13.65% B) 14.665%
C) 15.65% D) 16.65%
 
Answer & Explanation Answer: A) 13.65%

Explanation:

E=(1+i/n)^n-1

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