Question

60% of what number is 21

Answer 1

60% of 35 is 21 

Change the percentage (60) into a decimal by dividing it over 100:
$\frac{60}{100} = 0.6$

Divide 21 by the decimal:
$\frac{21}{0.6} = 35$

Answer 2

'of' in mathematics means multiplication
'is' in mathematics means equal

Translating 60% of what number is 21 into an equation, we get:

60% * x = 21

60%, or 60 percent, is 60 over 100 which is 60/100. This can be simplified to 3/5.

3/5 * x = 21

Multiply both sides by 5.

3/5 * 5 * x = 21 * 5

3x = 105

Divide 3 on both sides.

3x/3 = 105/3

x = 35

60% of 35 is 21.