# Percentages Quiz Set 015

### Question 1

If 82 is m% of p, and B is p% of m, then what is B?

A

82.

B

92.

C

72.

D

102.

Soln.
Ans: a

Let 82 = A, so A = \$m/100\$ × p = \$p/100\$ × m. = B, so A and B are same.

### Question 2

The service tax is 5%. A person receives a telephone bill amounting to Rs. 630. How much was the bill excluding tax?

A

Rs. 600.

B

Rs. 610.

C

Rs. 590.

D

Rs. 620.

Soln.
Ans: a

Let the calls be for Rs. x. The total bill is x + 5% of x = \${21x}/20 = 630\$, which gives x = Rs. 600.

### Question 3

A carton contains 8000 led bulbs, some of them are red, some green and others are blue. How many are green if 3% are red and 5% are blue?

A

7360.

B

7460.

C

7260.

D

7560.

Soln.
Ans: a

The percentage of green is 100 - (3 + 5) = 92. So number of green bulbs = \$92/100\$ × 8000 = 7360.

### Question 4

The service tax is 5%. A person receives a telephone bill amounting to Rs. 840. How much was the bill excluding tax?

A

Rs. 800.

B

Rs. 810.

C

Rs. 790.

D

Rs. 820.

Soln.
Ans: a

Let the calls be for Rs. x. The total bill is x + 5% of x = \${21x}/20 = 840\$, which gives x = Rs. 800.

### 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}\$%.

Updated on 2017-05-17.

Posted by Parveen(Hoven),
Aptitude Trainer