Converting Percentages to “How Many”

Example

A survey of 40 children showed that 25% liked playing football. How many children liked playing football?

Here, The total number of children are 40. Out of these, 25% like playing football.

(i) 25% of 40

Number of children who like playing football = 25/100 × 40 = 10.

(ii) Out of 100, 25 like playing football So out of 40,

Number of children who like playing football = 25/100 × 40 = 10.

Hence, 10 children out of 40 like playing football.

Example

Rahul bought a sweater and saved Rs. 200 when a discount of 25% was given. What was the price of the sweater before the discount?

Rahul has saved Rs. 200 when price of sweater is reduced by 25%. This means that 25% reduction in price is the amount saved by Rahul.

(i) 25% of the original price = Rs. 200

Let the price (in Rs.) be x.

So, 25% of x = 200 or 25/100 xx x = 200

or, x/4 = 200 or x = 200 × 4

Therefore, x = 800.

(ii) Rs. 25 is saved for every Rs. 100

Amount for which Rs. 200 is saved = 100/25 xx 200 = Rs. 800

Thus both obtained the original price of sweater as Rs. 800.

Example

For summative evaluation in a certain school, 720 of the 1200 children were awarded A grade in Maths. What is the percentage of students getting A grade?

Suppose the students getting A grade are A%.

"A"/100 = 720/1200

∴ "A"/100 xx 100 = 720/1200 xx 100

∴ A = 60

∴ 60% students got A grade.

Example

A certain Organization adopted 18% of the 400 schools in a district. How many schools did it adopt?

Here, 18% means 18 schools adopted out of a total of 100.
The total number of schools is 400.
Suppose the number of schools adopted is A.

"A"/400 = 18/100

"A"/400 xx 400 = 18/100 xx 400

∴ A = 72.

∴ The number of schools adopted is 72.

If you would like to contribute notes or other learning material, please submit them using the button below.

Shaalaa.com

Converting Percentages to “How Many” [00:07:36]
S
0%