Question

Question 1(c)
Set up equations and solve them to find the unknown numbers in the following cases:
If I take three-fourth of a number and add 3 to it, I get 21.

Answer 1

Let the number be z.
According to the question, $\frac{3}{4}z+3=21$
$\Rightarrow \frac{3}{4}z=21-3\Rightarrow \frac{3z}{4}=18\Rightarrow 3z=18\times 4\Rightarrow 3z=72\Rightarrow z=\frac{72}{3}\Rightarrow z=24$