This set of Aptitude Questions and Answers (MCQs) focuses on “Increase or Decrease”.
1. A number is increased by 20% and then decreased by 25%. Find the percentage change.
a) 10% increase
b) 10% decrease
c) 20% increase
d) 20% decrease
View Answer
Explanation: Let the number be 100.
Initial increase percentage is 20%.
The number after first increase = 100 + 20% of 100 = 100 + 20 = 120
Second increase is 25%.
The number after second step = 120 – 25% of 120 = 120 – 30 = 90
The final value of the number = 90
The initial value of the number assumed = 100
Difference between the numbers = 100 – 90 = 10
Percentage change = 10 / 100 * 100 = 10% decrease
2. A number is decreased by 20% and then increased by 25%. Find the percentage change.
a) 2% change
b) 1% change
c) 0% change
d) (-) 1% change
View Answer
Explanation: Let the number be 100.
The initial change is 20% decrease.
Initial change = 100 – 20% of 100 = 100 – 20 = 80
The second change is 25% increase.
Second change = 80 + 25% of 80 = 80 + 20 = 100
The initial and the final value are same hence no change or 0% change.
3. An employee’s salary is increased by 30% during the first year but due to global pandemic he faced a salary cut of 20%. If he received 20000 during the initial stage, find his current salary.
a) 20,000
b) 20,200
c) 20,500
d) 20,800
View Answer
Explanation: His salary at the beginning = 20,000
His salary hike = 30%
Salary hike = 30% of 20,000
30% of 20,000 = 30 * 20,000 / 100 = 6000
His salary after the hike = 20,000 + 6,000 = 26,000
Salary cut due to pandemic = 20%
Salary cut = 20% of 26,000 = 20 * 26,000 / 100 = 5200
Salary after cut = 26,000 – 5,200 = 20,800
4. If the salaries of two people a and b are increased by 40% and 50% respectively and the final salary after the promotion is same, find the ratio of their initial salaries.
a) 15 : 14
b) 14 : 13
c) 13 : 12
d) 12 : 11
View Answer
Explanation: Let their initial salaries be x and y, respectively.
Increment of a is 40% and increment of b is 50%.
As per the question x + 40% of x is equal to y + 50% of y.
X + 40% of x = x + 40x / 100 = x + 2x / 5 = 7x / 5
Y + 50% of y = y + 50x / 100 = y + y / 2 = 3y / 2
7x / 5 = 3y / 2
14x = 15y
x / y = 15 / 14
x : y = 15 : 14
5. After 50% increment followed by 25% cut A’s salary is 18,000. Find his initial salary.
a) 12,000
b) 14,000
c) 16,000
d) 18,000
View Answer
Explanation: Let his initial salary be x.
The first change in his salary is an increment of 50%.
X + 50% of x = x + x / 2 = 3x / 2
The second change in his salary was a 25% cut.
3x / 2 – 25% of 3x / 2 = 3x / 2 – (3x * 25) / 2 * 100 = 3x / 2 – 3x / 8
12x / 8 – 3x / 8 = 9x / 8
9x / 8 = 18,000
X = 18000 / 9 * 8 = 2,000 * 8 = 16,000
6. A number is increased by 20% twice and then decreased by 20%. Find the Percentage change.
a) 14.2% increased
b) 14.2% decreased
c) 15.2% increased
d) 15.2% decreased
View Answer
Explanation: Let the number be 100.
The initial change is 20% increase.
100 + 20% of 100 = 100 + 20 = 120
The second change is 20% increase.
120 + 20% of 120 = 120 + 24 = 144
The final change is 20% decreased.
144 – 20% of 144
144 – 20 * 144 / 100 = 144 – 28.8 = 115.2
Final value – initial value = 115.2 – 100 = 15.2
The percentage change = 15.2 / 100 * 100 = 15.2% increase
7. Two numbers are decreased by 20% and 25%, respectively. If the ratio of the numbers initially was 1 : 2, find their ratios now.
a) 11 : 18
b) 10 : 17
c) 9 : 16
d) 8 : 15
View Answer
Explanation: Let the first number be 100.
As per the question the second number is twice of the first number initially, the second number is 200.
The percentage change of the first number is 20% decreased.
100 – 20% of 100 = 100 – 20 = 80
The percentage change of the second number is 25% decreased.
200 – 25% of 200 = 200 – 50 = 150
Their ratios now = 80 : 150 = 8 : 15
8. The annual salaries of an employee is increased by 15% half yearly, but due to the pandemic his salary was decreased by 2,000 after his second increment. If his initial salary was 15,000, find his salary at the end of 6 months.
a) 17,250
b) 18,250
c) 19,250
d) 15,650
View Answer
Explanation: Here in the question it is given that his salary is increased by 15% after every 6 months and as per the question, he got a cut of 2,000 after his second increment that is after a year. But in the question, it is asked about his salary after 6 months. So, the solution of this question will be just based on his salary after 6 months with a hike of 15%.
His salary after 6 months = 15,000 + 15% increment
15,000 + 15% of 15,000
15,000 + 15 * 15,000 / 100 = 15,000 + 2,250
= 17,250
9. Which of the following percentage is equivalent to 20% then + 25% then + 50%?
a) 100%
b) 125%
c) 95%
d) 90%
View Answer
Explanation: To calculate the percentage we need a constant.
Let the value of constant be 100.
First change = 20%
100 + 20% of 100 = 100 + 20 = 120
Second change = 25%
120 + 25% of 120 = 120 + 30 = 150
Third change = 150 + 50% of 150 = 150 + 75 = 225
The total difference of initial value and final value:
225 – 100 = 125
Percentage change = 125 * 100 / 100 = 125%
10. A number is increased by 80% then decreased by 50% and finally increased by 125%. Find the percentage change.
a) 102.5%
b) 112.5%
c) 202.5%
d) 212.5%
View Answer
Explanation: Let the initial value be 100.
The first change is 80% increased.
100 + 80% of 100 = 100 + 80 = 180
The second change is 50% decreased.
180 – 50% of 180 = 180 – 90 = 90
The final change is 125% increased.
90 + 125% of 90 = 90 + 112.5 = 202.5
The change = 202.5 – 100 = 102.5
Percentage change = 102.5 / 100 * 100 = 102.5
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