 # Average Questions Quiz for SBI PO Pre, IBPS PO Pre, SBI Clerk, IBPS Clerk, 2018

Important for :
1
In a class with a certain number of students if one new student weighing 50 kg is added, then average weight of class is increased by 1 kg. If one more student weighing 50 kg is added, then the average weight of the class increases by 1.5 kg over the original average. What is the original average weight (in kg) of the class?
» Explain it
D
Let x be the number of students in the class and y be the average weight of the class
Now according to question,
 xy + 50 = y + 1 x + 1
x + y = 49 .......... (i) Again,
 xy + 50 + 50 = y + 1.5 x + 2

1.5x + 2y = 97 .......... (ii) From equation (i) and (ii), we get y = 47

Hence, option (D) is correct.

2
While purchasing an item that costs Rs. 400, one has to pay sales tax at the rate of 7% and on another item costing Rs. 6400, the rate of sales tax was 9%. The percent of sales tax one has to pay, taking these items together on an average is?
» Explain it
D
 Sales tax on the article sold at Rs. 400 = 400 × 7 = 28 100

Sales tax on the article sold at Rs. 6400
 = 6400 × 9 = 576 100

Total tax = 28 + 576 = 604

 Percentage sales tax = 604 × 100 = 151 = 8 15 % 6800 17 17

Hence, option (D) is correct.

3
The average salary of male employees in a firm was Rs. 6000 and that of females was Rs. 5600. The mean salary of all the employees was Rs. 5800. What is the % of female employees?
» Explain it
B
Average salary of male employees = Rs. 6000

Average salary of female employees = Rs. 5600

Mean salary = Rs. 5800

By using alligation

 (6000) (5600) \ / (5800) / \ 200 200

∴ The ratio of male : female = 200 : 200 = 1 : 1

 Hence, % of female employees = 1 × 100 = 50% 2

Therefore, option (B) is correct.

4
The average salary of 65 workers is Rs. 5680 out of which average salary of 31 workers is Rs. 2356 and that of 23 workers is Rs. 4589. What is the average salary of remaining workers?(value in approximate)
» Explain it
C
Total salary of 65 workers =  65 × 5680 = Rs. 369200

Total salary of 31 workers = 31 × 2356 = Rs. 73036

Total salary of 23 workers = 23 × 4589 = Rs. 105547

No. of remaining workers = 65 – 31 – 23 = 65 – 54 = 11

Total Salary of 11 workers =  369200 – 73036 – 105547 = 369200 – 178583 = Rs. 190617

 Required average = 190617 = 17329(approx) 11

Hence, option C is correct.

5
The average sales of a mobile shopkeeper was 15 mobiles per week, to increase the sales he decided to tie up with a finance company for providing mobiles to customers on installment. After the launch of this scheme his average sales increased to 21 mobile per week. The annual percentage increase in the sales of mobile was:
» Explain it
A
The average rate of percentage increase in both the cases- weekly and yearly will be the same.

 Therefore, annual percentage in sales = 21 – 15 × 100 15

 = 600 = 40% 15

Hence, option A is correct.