## Steps involved in finding a percent of a given number

*Step I*– Obtain the number, say x.

*Step II*– Obtain the required percent, say P %.

* Step III*– Multiply x by P and divide by 100 to obtain the required P % of x

i.e., P% of x = \(\frac{ P}{ 100}\) * x

## Illustrative Examples

**Example 1:** Find

(i) 30% of Rs 180 (ii) 13% of Rs 6500 (iii) 16% of 25 litres

**Solution.** We know that P% of x is equal to \(\frac{ P }{ 100}\) * x. So, We have

(i) 30% of Rs 180 = Rs ( \(\frac{ 30 }{ 100}\) x 180) = Rs 54

(ii) 13% of Rs 6500 = Rs ( \(\frac{ 13 }{ 100}\) x 6500 ) = Rs 845

(iii) 16% of 25 litres = Rs ( \(\frac{ 16 }{ 100}\) x 25) = 4 litres

**Example 2:** If 23% of a is 46, then find a.

**Solution.** We have,

23% of a = \(\frac{ 23 }{ 100}\) x a.

But, 23% of a is given as 46.

Therefore, \(\frac{ 23 }{ 100}\) x a => a = 46 x \(\frac{ 100 }{ 23 }\)

=> a = 200

**Example 3:** 72% of 25 students are good at Mathematics. How many are not good at it?

**Solution.** We have,

Number of students who are good at Mathematics

= 72% of 25

= \(\frac{ 72 }{ 100}\) x 25 = 18