# 130% of what number is 1170?

Aug 8, 2016

$900$

#### Explanation:

As the number has been increased by 30% to become 1170, we are expecting a number smaller than 1170 as the answer.

DO NOT be tempted to just subtract 30%. 30% of a smaller number is not the same as 30% of a larger number.

One method is to write an equation stating exactly what is asked in the question. "130% of some number is 1170."

$\frac{130}{100} \times x = 1170$

$x = 1170 \times \frac{100}{130} \text{ by dividing by 130, we are finding 1%}$

$x = 900$

OR, by direct proportion:

$\frac{130}{100} = \frac{1170}{x}$

$x = \frac{100 \times 1170}{130}$

$x = 900$

[Quick check: 130% =1.3 so $900 \times 1.3 = 1170$]