Quantitative Aptitude - Arithmetic Ability Questions

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

Report Error

View Answer Report Error Discuss

Filed Under: Average

183 59379
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.

Report Error

View Answer Report Error Discuss

Filed Under: Probability

75 59130
Q:

Find the next number in the series

 

143 143 136 110 ?

A) 91 B) 35
C) 47 D) 69
 
Answer & Explanation Answer: C) 47

Explanation:

The next number in the series is

143 143 136 110

      0    7      26 (Differences)

 13 - 1 , 23 - 1, 33 - 1, 43 - 1,...Now the next number is given by110 - (43 - 1) = 110 - 63 = 47.

Report Error

View Answer Report Error Discuss

Filed Under: Odd Man Out
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Analyst , Bank Clerk , Bank PO

8 58897
Q:

A and B are partners in a business. A contributes 1/4 of the capital for 15 months and B received 2/3 of the profit. For how long B's money was used ?

A) 3 months B) 6 months
C) 10 months D) 12 months
 
Answer & Explanation Answer: C) 10 months

Explanation:

Let the total profit be Rs. z. Then,

B's share = Rs. 2z/3,  A's share = Rs. ( z - 2z/3 ) = Rs. z/3.

A : B = z/3 : 2z/3 = 1:2

Let the total capital be Rs, X and suppose B's money was used for x months. Then.

(1(x) / 4 * 15) / (3x) / 4 * y) = 1/2 <=> y = (15 * 2 / 3) = 10 .

 Thus, B's money was used for 10 months.

Report Error

View Answer Report Error Discuss

Filed Under: Partnership

125 58671
Q:

How many arrangements can be made out of the letters of the word COMMITTEE, taken all at a time, such that the four vowels do not come together?

A) 216 B) 45360
C) 1260 D) 43200
 
Answer & Explanation Answer: D) 43200

Explanation:

There are total 9 letters in the word COMMITTEE in which there are 2M's, 2T's, 2E's.

The number of ways in which 9 letters can be arranged = 9!2!×2!×2! = 45360

 

There are 4 vowels O,I,E,E in the given word. If the four vowels always come together, taking them as one letter we have to arrange 5 + 1 = 6 letters which include 2Ms and 2Ts and this be done in 6!2!×2! = 180 ways.

 

In which of 180 ways, the 4 vowels O,I,E,E remaining together can be arranged in 4!2! = 12 ways.

 

The number of ways in which the four vowels always come together = 180 x 12 = 2160.

 

Hence, the required number of ways in which the four vowels do not come together = 45360 - 2160 = 43200

Report Error

View Answer Report Error Discuss

60 58506
Q:

If 6th March, 2005 is Monday, what was the day of the week on 6th March, 2004?

A) Sunday B) Saturday
C) Tuesday D) Wednesday
 
Answer & Explanation Answer: A) Sunday

Explanation:

The year 2004 is a leap year. So, it has 2 odd days.

But, Feb 2004 not included because we are calculating from March 2004 to March 2005.

So it has 1 odd day only.

The day on 6th March, 2005 will be 1 day beyond the day on 6th March, 2004.

Given that, 6th March, 2005 is Monday.

6th March, 2004 is Sunday (1 day before to 6th March, 2005).

Report Error

View Answer Report Error Discuss

Filed Under: Calendar

248 58334
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.

Report Error

View Answer Report Error Discuss

Filed Under: Average

103 58286
Q:

A man walked diagonally across a square lot. Approximately, what was the percent saved by not walking along the edges?

A) 30 B) 40
C) 50 D) 60
 
Answer & Explanation Answer: A) 30

Explanation:

Let the side of the square(ABCD) be x meters.

 

Then, AB + BC = 2x metres.

 

AC = 2x = (1.41x) m.

 

Saving on 2x metres = (0.59x) m.

 

Saving % =0.59x2x*100 = 30% (approx)

Report Error

View Answer Report Error Discuss

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

96 58064