# Percentages Quiz Set 013

### Question 1

The number of online customers increased from 625 to 2075. What is the percentage increase?

A

232 %.

B

233 %.

C

231 %.

D

\$78{1/3}\$ %.

Soln.
Ans: a

The increase is 2075 - 625 = 1450. The percentage increase is \$1450/625\$ × 100 = 232.

### Question 2

A clerk multiplied a number by 5/4 instead of 4/5. What is the percentage of error?

A

36 %.

B

38 %.

C

34 %.

D

40 %.

Soln.
Ans: a

If the actual figure is x, the error is \${5x}/4\$ - \${4x}/5\$ = \${5^2x - 4^2x}/{5 × 4}\$ = \${9x}/20\$, so %-error = \${(9x)/20}/{(5x)/4}\$ × 100 = \${9 × 4}/{20 × 5}\$ × 100 = 36%.

### Question 3

If 57 is m% of p, and B is p% of m, then what is B?

A

57.

B

67.

C

47.

D

77.

Soln.
Ans: a

Let 57 = A, so A = \$m/100\$ × p = \$p/100\$ × m. = B, so A and B are same.

### Question 4

Mr. X who spends 62% of his salary is able to save Rs. 342. What is his salary?

A

Rs. 900.

B

Rs. 1000.

C

Rs. 800.

D

Rs. 1100.

Soln.
Ans: a

Let the salary be x. His saving% is 100 - 62 = 38, so 38% of x = 342, which gives x = \$342/38\$ × 100 = Rs. 900.

### Question 5

A number is first increased by 40%. By what percent must it be reduced so as to restore it to its previous value?

A

\$28{4/7}\$ %.

B

\$34{1/2}\$ %.

C

\$21{4/9}\$ %.

D

\$24{5/9}\$ %.

Soln.
Ans: a

Let us derive the shortcut formula first, so that you can remember it and use it when the need arises. Suppose the number is 100, and let the increase be x%. The number becomes 100 + x. Let us suppose that it has to be reduced by p% to restore it to 100. Then, (100 + x) - p × \$(100 + x)/100\$ = 100. We can cancel away 100, and easily simplify it to p = \${100 × x}/{100 + x}\$ = \${100 × 40}/{100 + 40}\$ = \${200/7}\$, which is same as: \$28{4/7}\$%. This Blog Post/Article "Percentages Quiz Set 013" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-05-12