Question

If the cost of 5 bars of a soap is Rs. 30, then the cost of one dozen bars is

(a) Rs 60
(b) Rs 120
(c) Rs 72
(d) Rs 140

Answer 1

(c) Rs. 72
Let the cost of one dozen bars be Rs. x.

$$\begin{gathered} \therefore \frac{30}{5}=\frac{x}{12} \\ \Rightarrow x=\frac{30}{5}\times 12=\mathrm{Rs}.72 \end{gathered}$$

Cost of one dozen (12) bars = Rs. 72