Percentage - Aptitude MCQ Questions and Solutions with Explanations

11

5 kg of metal A and 20 kg of metal B are mixed to form an alloy. The percentage of metal A in the alloy is ?

A) 20% B) 25% C) 40% D) None of these

Discuss

Answer & Solution

Answer: Option A

Solution:

Weight of metal A = 5kg
Total weight of the alloy :
= (5 + 20) kg
= 25 kg
∴ Required percentage :
$$\eqalign{ & = \left( {\frac{5}{{25}} \times 100} \right)\% \cr & = 20\% \cr} $$

12

23% of 8040 + 42% of 545 = ? % of 3000

A) 56.17 B) 63.54 C) 69.27 D) 71.04 E) None of these

Discuss

Answer & Solution

Answer: Option C

Solution:

Let 23% of 8040 + 42% of 545 = x% of 3000
Then,
$$\left( {\frac{{23}}{{100}} \times 8040} \right) + \left( {\frac{{42}}{{100}} \times 545} \right)$$ = $$\left( {\frac{x}{{100}} \times 3000} \right)$$
$$\eqalign{ & \Rightarrow 30x = 1849.2 + 228.9 \cr & \Rightarrow 30x = 2078.1 \cr & \Rightarrow x = \frac{{2078.1}}{{30}} \cr & \Rightarrow x = 69.27 \cr} $$

13

While purchasing one item costing Rs. 400, I had to pay the sales tax at 7% and on another costing Rs. 6400, the sales tax was 9%. What percent of the sales tax I had to pay, taking the two items together on an average ?

A) 8% B) $$8\frac{13}{17}$$% C) $$8\frac{15}{17}$$% D) $$8\frac{1}{2}$$%

Discuss

Answer & Solution

Answer: Option C

Solution:

Total sales tax paid = 7% of Rs. 400 + 9% of Rs. 6400
= Rs. $$\left( {\frac{7}{{100}} \times 400 + \frac{9}{{100}} \times 6400} \right)$$
= Rs. (28 + 576)
= Rs. 604
Total cost o the items :
= Rs. (400 + 6400)
= Rs. 6800
∴ Required percentage
$$\eqalign{ & = \left( {\frac{{604}}{{6800}} \times 100} \right)\% \cr & = 8\frac{{15}}{{17}}\% \cr} $$

14

The difference between 54% of a number and 26% of the same number is 22526. What is 66% of that number ?

A) 48372 B) 49124 C) 51218 D) 53097 E) None of these

Discuss

Answer & Solution

Answer: Option D

Solution:

Let the number be = $$x$$
Then,
⇒ 54% of $$x$$ - 26% of $$x$$ = 22526
⇒ $$\frac{{54}}{{100}}$$ $$x$$ - $$\frac{{26}}{{100}}$$ $$x$$ = 22526
⇒ $$\frac{{28}}{{100}}$$ $$x$$ = 22526
⇒ $$x$$ = $$\left( {\frac{{22526 × 100}}{28}} \right)$$
⇒ $$x$$ = 80450
∴ 66% of 80450 = $$\left( {\frac{{66}}{{100}} \times 80450} \right)$$
= 53097

15

If 75% of a number is added to 75, then the result is the number itself. The number is :

A) 50 B) 60 C) 300 D) 400

Discuss

Answer & Solution

Answer: Option C

Solution:

Let the number be x
Then,
75% of x + 75 = x
⇔ x - $${\frac{{75}}{100}}$$ x = 75
⇔ x - $${\frac{{3}}{4}}$$ x = 75
⇔ $${\frac{{x}}{4}}$$ = 75
⇔ x = 300

16

40% of 60% of 32% of an amount is Rs. 432. What is the amount ?

A) Rs. 5000 B) Rs. 5600 C) Rs. 6400 D) None of these

Discuss

Answer & Solution

Answer: Option D

Solution:

Let the required amount be Rs. x
Then, 40% of 60% of 32% of x = 432
⇒ $$\frac{{40}}{{100}} \times \frac{{60}}{{100}} \times \frac{{32}}{{100}}$$ × $$x$$ = 432
⇒ x = $$\frac{{432 \times 100 \times 100 \times 100}}{{40 \times 60 \times 32}}$$
⇒ x = 5625

17

In a test, minimum passing percentage for girls and boys is 35% and 40% respectively. A boy scored 483 marks and failed by 117 marks. What is the minimum passing marks for girls ?

A) 425 B) 500 C) 520 D) 625 E) None of these

Discuss

Answer & Solution

Answer: Option E

Solution:

Let the maximum marks be x
Then, 40% of x = 483 + 117
⇒ $$\frac{{40x}}{{100}}$$ = 600
⇒ x = $$\left( {\frac{{600 \times 100}}{{40}}} \right)$$
⇒ x = 1500
∴ Minimum passing marks for girls :
= 35% of 1500
= $$\left( {\frac{{35}}{{100}} \times 1500} \right)$$
= 525

18

A clothing supplier stores 800 coats in a warehouse, of which 15 percent are full-length coats. If 500 of the short-length coats are removed form the warehouse, then what percent of the remaining costs are full length ?

A) 5.62% B) 9.37% C) 35% D) 40%

Discuss

Answer & Solution

Answer: Option D

Solution:

Number of short length coats before removal :
= (100 - 15)% of 800
= 85% of 800
= $$\left( {\frac{{85}}{{100}} \times 800} \right)$$
= 680
Number of short length coats after removal :
= (680 - 500)
= 180
Total number of coats after removal :
= (800 - 500)
= 300
Number of full length coats removal :
= (300 - 180)
= 120
∴ Required percentage :
= $$\left( {\frac{{120}}{{300}} \times 100} \right)$$ %
= 40%

19

Peter could save 10% of his income. But two years later when his income is increased by 20%, he could save the same amount only as before. By how much percent has his expenditure increased ?

A) 22% B) $$22\frac{2}{9}\% $$ C) $$23\frac{1}{3}\% $$ D) 24%

Discuss

Answer & Solution

Answer: Option B

Solution:

Let original income - Rs. 100
Then, saving = Rs. 10 and expenditure = Rs. 90
New income = Rs. 120
New saving = Rs. 10
New expenditure = Rs. (120 - 10) = Rs. 110
Increase in expenditure = Rs. (110 - 90) = Rs. 20
∴ Income % :
$$\eqalign{ & = \left( {\frac{{20}}{{90}} \times 100} \right)\% \cr & = 22\frac{2}{9}\% \cr} $$

20

A papaya tree was planted 2 years ago. It grows at the rate of 20% every year. If at present, the height of three is 540 cm, what was it when the tree was planted ?

A) 324 cm B) 375 cm C) 400 cm D) 432 cm

Discuss

Answer & Solution

Answer: Option B

Solution:

Height of the tree 2 years ago :
$$\eqalign{ & = \frac{{540}}{{{{\left( {1 + \frac{{20}}{{100}}} \right)}^2}}}cm \cr & = \left( {540 \times \frac{5}{6} \times \frac{5}{6}} \right)cm \cr & = 375\,\,cm \cr} $$