Quantitative Aptitude - Arithmetic Ability Questions

Q:

In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?

A) 1/3 B) 3/5
C) 8/21 D) 7/21
 
Answer & Explanation Answer: A) 1/3

Explanation:

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

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

            = event that the ball drawn is blue.

n(E) = 7.

P(E) = n(E)/n(S) = 7/21 = 1/3.

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Filed Under: Probability

77 60433
Q:

What will come in place of the question mark(?) in the following question ?

56% of 870 + 82% of 180 = 32% of 90 + ?

A) 777 B) 666
C) 606 D) 789
 
Answer & Explanation Answer: C) 606

Explanation:

56% of 870 = 56x870/100 = 487.20

82% of 180 = 82x180/100 = 147.60

32% of 90 = 32x90/100

487.20 + 147.6 - 28.8  =  ?

? = 634.8  - 28.8

? = 606.

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

8 60323
Q:

The ratio between the perimeter and the breadth of a rectangle is 5 : 1. If the area of the rectangle is 216 sq. cm, what is the length of the rectangle?

A) 16 B) 18
C) 20 D) 22
 
Answer & Explanation Answer: B) 18

Explanation:

2l+bb=51      => 2l + 2b = 5b     => 3b = 2l 

b=(2/3)l

 

Then, Area = 216 cm2 

=> l x b = 216     => l x (2/3)l =216 

l = 18 cm.

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

50 60100
Q:

If x2 + kx + k = 0 has no solution, then the value of k will satisfy

 

A) k < 4 B) k > -4
C) k > 4 D) 0 < k < 4
 
Answer & Explanation Answer: D) 0 < k < 4

Explanation:
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Filed Under: Simplification
Exam Prep: Bank Exams
Job Role: Bank Clerk

7 59927
Q:

The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is :

A) 35 B) 36.5
C) 40 D) 42
 
Answer & Explanation Answer: B) 36.5

Explanation:

Correct Sum = (36 * 50 + 48 - 23) = 1825.

Correct mean = = 1825/50 = 36.5

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Filed Under: Average

183 59885
Q:

The average of 11 numbers is 10.9. If the average of the first six numbers is 10.5 and that of the last six numbers is 11.4, then the middle number is :

A) 10.5 B) 11.5
C) 12.5 D) 13.5
 
Answer & Explanation Answer: B) 11.5

Explanation:

Middle numbers  =  [(10.5 x 6 + 11.4 x 6) - 10.9 x 11] = (131.4 - 119-9) = 11.5.

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Filed Under: Average

103 59827
Q:

The L.C.M of two numbers is 495 and their H.C.F is 5. If the sum of the numbers is 100, then their difference is 

A) 10 B) 46
C) 70 D) 90
 
Answer & Explanation Answer: A) 10

Explanation:

Let the numbers be x and (100-x).

 

Then,x100-x=5*495

 

 =>  x2-100x+2475=0

 

 =>  (x-55) (x-45) = 0

 

 =>  x = 55 or x = 45

 

  The numbers are 45 and 55

 

Required difference = (55-45) = 10

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Filed Under: HCF and LCM

151 59820
Q:

23-[24-25-(26-27-28¯)]=?

 

 

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

Explanation:
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Filed Under: Simplification
Exam Prep: Bank Exams

16 59387