Question

Teacher says, 15% of first number is equal to 21% of the second number. So, 18% of first number will be what percent of second number?

Answer 1

Step-by-step explanation:

15 precent of 1st no. =21 precent of 2nd no.

1 precent of 1st no.=21/15 precent of 2nd no.

18 precent of 1st no.= 21/15 multiply18 precent of 2nd no.

=25.2 precent

Answer 2

So, 18% of the first number will be 25.2 % of the second number.

Let's understand a few concepts:

What is the percentage?

A percentage is a number or a ratio that is expressed in terms of a fraction of 100.

What is the percentage of a number?

If we have two numbers and we divide one number with the other and then multiply the obtained result by 100, we will get the result as the percentage of the number.

How to find the percentage of a number?

The percentage of a number can be found by using the following formula:

$\boxed{\bold{Percentage = \frac{Value}{Total \:value} \times 100}}$

Let's solve the given problem:

Let

"x" be the first number

"y" be the second number

15% of the first number is equal to 21% of the second number, so we can form the equation as,

$\frac{15}{100} \times x = \frac{21}{100} \times y$

$\implies 15 \times x = 21 \times y$

$\implies \frac{x}{y} = \frac{21}{15}$

$\implies \frac{x}{y} = \frac{7}{5}$ . . . (1)

We have,

18% of the first number = $\frac{18}{100} \times x$

Now, we get

[18% of the first number] = [z% of the second number]

⇒ $\frac{18}{100} \times x = \frac{z}{100} \times y$

⇒ $18 \times x = z \times y$

⇒ $z = \frac{18 \times x}{y}$

from (1)

⇒ $z = 18 \times \frac{7}{5}$

⇒ $\bold{z = 25.2\%}$

Thus, 18% of the first number will be 25.2% of the second number.

Learn more about the percentage of a number here:

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