Practice question on percentage (Quantitative Aptitude)

Square, Cube, indices and Surds

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Question no. 1

If two numbers are respectively 20% and 50% of a third number, what is the percentage of the first number to the second ?

looks_one 10

looks_two 20

looks_3 30

looks_4 40

Option looks_4 40

Solution :
First number = a
second number = b
third number = c
a = 0.2 c .....[1]
b = 0.5 c .......[2]
divide 1 from 2
a/b = 0.2/0.5
a = 0.4b
a is 40 % of b

Question no. 2

11% of which number is 33?

looks_one 300

looks_two 330

looks_3 33

looks_4 None of these

Option looks_one 300

Solution :
11% of x = 33

Question no. 3

Two-third of one-seventh of a number is 87.5% of 240. What is the number ?

looks_one 2670

looks_two 2450

looks_3 2205

looks_4 1470

option looks_3 2205

Solution :

Question no. 4

10% of the inhabitants of a village having died of cholera, a panic set in, during which 25% of the remaining inhabitants left the village. The population is then reduced to 4050. Find the number of original inhabitants.

looks_one 5000

looks_two 6000

looks_3 7000

looks_4 8000

Option looks_two 0

very soon 4

Question no. 5

If A’s salary is 25% higher than B’s salary, then how much per cent is B’s salary lower than A’s ?

looks_one 49/3 %

looks_two 20 %

looks_3 25 %

looks_4 100/3 %

Option looks_two 20 %

Solution :
A = 1.25 B
B = 0.8 A
B has salary of 80 % of A
it means B has 20 % less than A

Question no. 6

In a co-education school there are 15 more girls than boys. If the number of girls is increased by 10% and the number of boys is also increased by 16%, there would be nine more girls than boys. What is the number of students in the school?

looks_one 240

looks_two 225

looks_3 265

looks_4 245

Option looks_3 265

Solution :
Girls = G , Boys = B
G = B + 15
new no. of girls after 10 % increased = G₁ = G + 0.1G = 1.1 G
new no. of boys after 16 % increased = B₁ = B + 0.1B = 1.16 B
1.1 G = 1.16 B + 9
We have two equation : G = B + 15 , 1.1 G = 1.16 B + 9
B = 125
G = 140
No. of student in a school = 125 + 140 = 265

Question no. 7

In a class, 40% of the boys is same as 1/2 of the girls and there are 20 girls. Total number of students in the class is :

looks_one 70

looks_two 45

looks_3 35

looks_4 25

Option looks_two 45

Solution :
No. of girls = 20
Let no. of boys is x
40 % of x = 1/2 of no. of girls

total no. of students = 25 + 20 = 45

Question no. 8

In a shipment of 120 machine parts, 5 per cent were defective. In an another shipment of 80 machine parts, 10 per cent were also defective. For the two shipments combined, what per cent of the machine parts were defective?

looks_one 6.5 %

looks_two 7.0 %

looks_3 7.5 %

looks_4 8.0 %

Option looks_two 7.0 %

Solution :
No. of defective in first shipment = 5 % of 120 = .05 * 120 = 6
No. of defective parts in another shipment = 10 % of 80 = 0.1 * 80 = 8
Total no. of defects = 6 + 8 = 14
Total number of items of both the shipments = 120 + 80 = 200

Question no. 9

When the price of a radio was reduced by 20%, its sale increased by 80%. What was the net effect on the sale?

looks_one 44% increase

looks_two 44% decrease

looks_3 66% increase

looks_4 75% increase

Option looks_one 44% increase

Solution :
No. of units sell before reducing price = x
price of radio before reducing price = y
After reducing : No. of units sell = 1.8 x
price of radio = 0.8 y
Total revenue = 0.8y * 1.8x = 1.44 xy

Question no. 10

Lucknow Shatabdi Express has a capacity of 500 seats of which 10% are in the Executive class and the rest are chair cars. During one journey, the train was booked to 85% of its capacity. If Executive class was booked to 96% of its capacity, then how many chair car seats were empty during that journey?

looks_one 78

looks_two 73

looks_3 72

looks_4None of these

Option looks_two 73

Solution :
Executive class = 10 % of 500 = 0.1 * 500 = 50
chair cars = 500 - 50 = 450
96 % of executive class filled = .96 * 50 = 48
No. of booked = 85 % of 500 = 425
No. of chair car filled = 425 - 48 = 377
no. of chair emptied = 450- 377 = 73

Question no. 11

Of the 1000 inhabitants of a town, 60% are males of whom 20% are literates. If, of all the inhabitants, 25% are literates, then what % of the females of the town are literates ?

looks_one 22.5

looks_two 27.5

looks_3 32.5

looks_4 35.5

Option looks_3 32.5

solution :
Total inhabitant = 1000
No. of males = 60 % of 1000 = .60 * 1000 = 600
No. of literate male = 20 % of male = 0.2 * 600 = 120
total no. of literate = 25 % of 1000 = 0.25 * 1000 = 250
No. of female literate = 250 - 120 = 130

Question no. 12

If a% of x is equal to b% of y, then c% of y is what % of x ?

looks_one c %

looks_two ac/b %

looks_3 bc/a %

looks_4 abc %

Option looks_two ac/b %

Solution :
a % of x = b% of y

Question no. 13

Population of a district is 2,96,000 out of which 1,66,000 are males. 50% of the population is literate. If 70% males are literate, then the number of women, who are literate, is

looks_one 32,200

looks_two 31800

looks_3 66400

looks_4 48000

Option looks_two 31800

Solution :
Total population = 296000
male = 166000
No. of literate man = 70 % of 166000 = 0.70 * 166000 = 116200
total no. of ilterate = 50 % of 296000 = 148000
No. of ilterate woman = 148000 - 116200 = 31800

Question no. 14

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

looks_one 5.62 %

looks_two 9.37 %

looks_3 35 %

looks_4 40 %

Option looks_4 40 %

Solution :
Total coats = 800
full length coat = 15 % of 800 = 0.15 * 800 = 120
shorter length = 500
remaining coats = 800 - 500 = 300

Question no. 15

Mohan took half a pizza on Monday. He took half of what was left on Tuesday and so on. He followed this pattern for one week. How much of the pizza would he have taken during the week?

looks_one 99.22 %

looks_two 95 %

looks_3 98.22 %

looks_4 100 %

Option looks_one 99.22 %

Solution :