Question

If $\frac{45}{60}$ is equivalent to $\frac{3}{x}$, then x =

(a) 5
(b) 4
(c) 6
(d) 20

Answer 1

(b) 4

$$\begin{gathered} \frac{45}{60}=\frac{3}{x} \\ \mathrm{On}\mathrm{cross}-\mathrm{multiplying},\mathrm{we}\mathrm{get}: \\ 45\times x=3\times 60 \\ x=\frac{3\times 60}{45} \\ \Rightarrow x=\frac{180}{45} \\ \mathrm{On}\mathrm{dividing}\mathrm{the}\mathrm{numerator}\&\mathrm{denominator}\mathrm{by}\mathrm{the}\mathrm{HCF}\mathrm{of}180\hspace{0.17em}\&45,\mathrm{we}\mathrm{get}: \\ \frac{180÷45}{45÷45}=4 \end{gathered}$$