Question

What number must be subtracted from each term of ratio 17 : 33 so that the ratio becomes 7 : 15?

Answer 1

Suppose that x is the number that must be subtracted.
Then, (17 − x) : (33 − x) = 7 : 15

$$\begin{gathered} \Rightarrow \frac{17-x}{33-x}=\frac{7}{15} \\ \Rightarrow 255-15x=231-7x\Rightarrow 8x=255-231=24\Rightarrow x=3 \end{gathered}$$

Hence, 3 must be subtracted from each term of ratio 17 : 33 so that it becomes 7 : 15.