Ratio and Proportion — MATHS STD 7 — Question

1. 2 : 3 : 4

Solution:

As, $\frac{\text{a}}{2}=\frac{\text{b}}{3}=\frac{\text{c}}{4}$

$\Rightarrow\frac{\text{a}}{2}=\frac{\text{b}}{3}$ and $\frac{\text{b}}{3}=\frac{\text{c}}{4}$

$\Rightarrow3\text{a}=2\text{b}$ and $4\text{b}=3\text{c}$ (By cross multiplication)

$\Rightarrow\frac{\text{a}}{\text{b}}=\frac{2}{3}$ and $\frac{\text{b}}{\text{c}}=\frac{3}{4}$

$\Rightarrow\text{a}:\text{b}=2:3$

$\therefore\text{a}:\text{b}:\text{c}=2:3:4$

Hence, the correct alternative is option (a).