100+ Average Questions for IBPS, SBI PO, SO, Clerk - 1

Question: 1

Find the average of the following set of numbers 354, 281, 623, 518, 447, 702, 876.

(A) 520

(B) 540

(C) 543

(D) 548

Ans: C

Average = $$({354 + 281 + 623 + 518 + 447 + 702 + 876} / {7})$$ = $${3801}/{7}$$ = 543.

Question: 2

The average expenditure of a man for the first five months is Rs.1200 and for the next seven months is Rs.1300. if he saves Rs.2900 in that year, his monthly average income is

(A) Rs. 1400

(B) Rs. 1500

(C) Rs. 1600

(D) Rs. 1700

Ans: B

Average expenditure of a man for the first five month = Rs. 1200

Average expenditure of a man for the next seven month = Rs. 1300

Total annual expenditure of man

= Rs. (5 × 1200 + 7 × 1300) = Rs. (6000 + 9100) = Rs. 15100

Man saves = Rs. 2900

His total annual income = Rs. (15100 + 2900) = Rs. 18000

∴ Average monthly income = $${18000}/{12}$$ = Rs. 1500.

Question: 3

The average age of a husband and wife at the time of their marriage was 25 years. A son was born to them two years after their marriage. The present average age of all three of them is 24 years. How many years is it since the couple got married?

(A) 4 years

(B) 5 years

(C) 6 years

(D) 8 years

Ans: D

Sum of the ages of husband and wife at the time
of their marriage = (25 × 2) years = 50 years.

Sum of the ages of husband and wife
when their son was born = (50 + 2 × 2) years = 54 years.

Sum of the ages of husband, wife and son
at preset = (24 × 3) years = 72 years.

∴ Age of son = $${(72 - 54)}/{3}$$ = $${18}/{3}$$ = 6 years.

Hence, the couple got married (6 + 2) = 8 years ago.

Question: 4

The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?

(A) 0

(B) 1

(C) 19

(D) 20

Ans: C

Average of 20 numbers = 0.

∴ Sum of 20 numbers = (0 × 20) = 0.

It is quite possible that 19 of these numbers may be positive and if their sum is q, then 20th numbers is (-a).

Question: 5

The mean of 5 observations is 60, the mean of 10 observations is 30 and the mean of 15 observations is 20. The mean of all the 30 observations is

(A) 20

(B) 30

(C) 40

(D) 60

Ans: B

Required mean = $$({60 × 5 + 30 × 10 + 20 × 15}/{5 + 10 + 15})$$

= $$({300 + 300 + 300}/{30} )$$ = $${900}/{30}$$ = 30.

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