Question

Question:70% of x is 63. 1.Write an equation that shows the relationship of 70%, x, and 63. 2. Use your equation to find x. Show your reasoning.

Answer 1

"x" represents an unknown number, we know that 70% of x equals 63.

To calculate the percentage of a number you have to multiply the said number by the percentage, in this case, 70%, and divide the result by 100:

So the 70% of x can be calculated as:

$\frac{70\cdot x}{100}=63$

You can simplify this expression by solving the division

$\begin{gathered} \frac{70}{100}x=63 \\ \frac{7}{10}x=63 \\ 0.7x=63 \end{gathered}$

Then the expression that shows you the relationship is

$0.7x=63$

Using this expression you can determine the value of x, to do so you have to divide both sides of the equal sign by 0.7

$\begin{gathered} \frac{0.7x}{0.7}=\frac{63}{0.7} \\ x=90 \end{gathered}$

The value of x is 90