70 % of unknown number = 21
We multiply the percentage by a variable and make it = to the given value.
70% of n = 21
Change percent to decimal
70% = [tex] \frac{70}{100} [/tex] = 0.7
0.7n = 21
divide either sides by 0.7 to isolate n
[tex] \frac{0.7n}{0.7} [/tex] = [tex] \frac{21}{0.7} [/tex]
0.7 and 0.7 cancels out
n = 30
0.7 × 30 = 21
70 % of 30 is 21
An example has been attached below
% of a number = multiply % by number
value is the % of a number = divide % by value
