169+ Problems on Average With Explanation

Q:

Consider the following grouped frequency distribution:

x f

0-10 8

10-20 12

20-30 10

30-40 p

40-50 9

If the mean of the above data is 25.2, then what is the value of p?

A) 9	B) 10
C) 11	D) 12

Answer & Explanation Answer: C) 11

Explanation:

Mean = (sum of fixi/ (sum of f) = (8*5 + 12*15 + 10*25 + P*35 +9*45) / (8+12+10+P+9) = 25.2

(875 + 35P)/(39+P) = 25.2

P = 11

Report Error

View Answer Report Error Discuss

Filed Under: Average
Exam Prep: Bank Exams

0 19542

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.

Report Error

View Answer Report Error Discuss

Filed Under: Average

31 19524

Q:

The ratio of speeds of a car, a train and a bus is 5:9:4. The average speed of the car, the bus and the train is 72 km/hr together. What is the average speed of the car and the train together ?

A) 84 km/hr	B) 96 km/hr
C) 72 km/hr	D) 60 km/hr

Answer & Explanation Answer: A) 84 km/hr

Explanation:

Let the speeds of the car, train and bus be 5x, 9x and 4x km/hr respectively.
Average speed = 5x + 9x + 4x/3 = 18x /3 = 6x km/hr.
Also, 6x = 72 => x = 12 km/hr
Therefore, the average speed of the car and train together is = $\frac{5 x + 9 x}{2}$ = 7x = 7 x 12 = 84 km/hr.

Report Error

View Answer Report Error Discuss

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

20 17715

Q:

In a village the average age of n people is 42 years. But after the verification it was found that the age of a person had been considered 20 years less than the actual age, so the new average, after the correction,increased by 1. The value of n is :

A) 21	B) 20
C) 22	D) None of these

Answer & Explanation Answer: B) 20

Explanation:

It is the same as a person with 20 years more age replaces an existing person of the group ( or village)

Since the total age of the village having n persons, is being increased by 20 years and the average age of village is being increased by 1 year, hence there are total 20 people in the village.

Alternatively : ( n x 42 ) + 20 = ( n x 43 )

=> n=20

Report Error

View Answer Report Error Discuss

Filed Under: Average

14 17606

Q:

In an NGO the daily average wages of 20 illiterate employees is decreased from Rs.25 to Rs.10, thus the average salary of all the literate and illiterate employees is decreased Rs.10 per day. The No. of educated employees working in the NGO is :

A) 15	B) 20
C) 10	D) Data Insufficient

Answer & Explanation Answer: C) 10

Explanation:

Total employees = $\frac{(25 - 10) \times 20}{10} = 30$

Hence number of educated employees = 30-20 = 10

Report Error

View Answer Report Error Discuss

Filed Under: Average

32 17407

Q:

The runs scored by two batsmen over 7 matches are given below. Which batsman average was better ?

A) Batsman 1 - 39.3	B) Batsman 1 - 45.9
C) Batsman 1 - 43.2	D) Batsman 2 - 45.9

Answer & Explanation Answer: D) Batsman 2 - 45.9

Explanation:

Report Error

View Answer Report Error Discuss

Filed Under: Average
Exam Prep: Bank Exams

1 17059

Q:

The average weight of a group of boys is 30 kg. After a boy of weight 35 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?

A) 6	B) 8
C) 4	D) 5

Answer & Explanation Answer: C) 4

Explanation:

Let the number of boys in the group originally be x.
Total weight of the boys = 30x
After the boy weighing 35 kg joins the group, total weight of boys = 30x + 35
So 30x + 35 + 31(x + 1) = > x = 4.

Report Error

View Answer Report Error Discuss

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

7 16880

Q:

Find the average of first 30 multiples of 7.

A) 94.8	B) 99.6
C) 104.4	D) 108.5

Average Questions

Quick Links