FINDING PERCENT INCREASE OR DECREASE WORKSHEET

Problem 1 :

What is the percent increase from 5 to 8 ?

Problem 2 :

What is the percent decrease from  16 to 12.8 ?

Problem 3 :

A pair of shoes was originally priced $80. But a discount was given and it was sold for $74. Find the discount percent ? 

Problem 4 :

In a class, there were 20 boys and 15 girls in the last academic year. After 5 new boys are admitted in this academic year, the strength of the class becomes 43. Find the percentage increase in the number of girls in this academic year. 

Problem 5 : 

In the two quantities x and y, if x is increased by 10% and y is increased by 20%, what percentage of (x + y) will be increased ?

Problem 6 : 

If the length of a rectangle is increased by 10% and the width is decreased by 5%, by what percentage will the area of the rectangle increase or decrease?

1. Answer :

Step 1 :

Find the amount of change. 

Amount of change = Greater value - Lesser value 

Amount of change  =  8 - 5

Amount of change  =  3

Step 2 : 

Percentage change is 

= (Amount of change/Original amount) ⋅ 100 %

= (3/5) ⋅ 100%

= 0.6 ⋅100 %

= 60 %

So, the percent increase from 5 to 8 is 60%.

2. Answer :

Step 1 :

Find the amount of change. 

Amount of change = Greater value - Lesser value 

Amount of change  =  16 - 12.8

Amount of change  =  3.2

Step 2 : 

Percentage change is 

=  (Amount of change / Original amount) ⋅ 100 %

=  (3.2 / 16) ⋅ 100%

=  20%

So, the percent decrease from 16 to 12.8 is 20%.

3. Answer :

Step 1 :

Find the actual discount : 

Discount  =  80 - 74

Discount  =  $6

Step 2 :

Discount percent is

=  (Discount / Original price) ⋅ 100 %

=  (6 / 80) ⋅ 100 %

=  7.5%

So, the discount percent is 7.5%.

4. Answer :

Details of students strength in the last academic year :

No. of boys  =  20

No. of girls  =  15

Total  =  35

Details of students strength in this academic year :

No. of boys  =  20 + 5  =  25

Total  =  43

No. of girls  =  43 - 25  =  18

No. of new girls admitted in this academic year :

=  No. of girls in this year - No. of girls in the last year 

=  18 - 15

=  3

Percentage increase in the number of girls is

=  (3 / 15) ⋅ 100 %

=  (1 / 5) ⋅ 100%

=  20%

So, the percentage increase in the number of girls in this academic year is 20.

5. Answer :

Let the values of x and y be 100 each. 

Then, the sum of x and y is 

x + y  =  200

After x is increased by 10% and y is increased by 20%, the sum is 

1.1x + 1.2y  =  1.1(100) + (1.2)100

1.1x + 1.2y  =  110 + 120

1.1x + 1.2y  =  230

Amount of change is 

=  230 -  200

=  30

Percentage increase of (x + y) is 

=  (30 / 200) ⋅ 100 %

=  15%

So, (x + y) will be increased by 15 percentage.

6. Answer :

Let 10 be the length and 10 be the width of a rectangle.

Area of the rectangle = 10 ⋅ 10

= 100 square units

When length is increased by 10%,

new length = (100 + 10)% of 10

= 110% of 10

= 1.1 ⋅ 10

= 11

When the width is decreased by 5%,

new width = (100 - 5)% of 10

= 95% of 10

= 0.95 ⋅ 10

= 9.5

After 10% increase in length and 5% decrease in width,

area of the rectangle = 11 ⋅ 9.5

= 104.5 square units

104.5 - 100 = 4.5

When the length is increased by 10% and width is decreased by 5%, area of the rectangle increases by 4.5%.

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.