Question:
Tick (✓) the correct answer:
Ravi buys some toffees at 5 for a rupee and sells them at 2 for a rupee. His gain per cent is
(a) 30%
(b) 40%
(c) 50%
(d) 150%
Solution:
(d) 150%
L. C. M of 5 and $2=(5 \times 1 \times 2)=10$
Let 10 be the number of toffees bought.
CP of 5 toffees $=$ Rs 1
$\mathrm{CP}$ of 1 toffee $=\mathrm{Rs}\left(\frac{1}{5}\right)$
$\therefore \mathrm{CP}$ of 10 toffees $=\mathrm{Rs}\left(\frac{1}{5} \times 10\right)$
= Rs 2
SP of 2 toffees $=$ Rs 1
SP of 1 toffee $=$ Rs $\left(\frac{1}{2}\right)$
$\therefore$ SP of 10 toffees $=$ Rs $\left(\frac{1}{2} \times 10\right)$
= Rs 5
Gain $=$ Rs $(5-2)$
= Rs 3
Gain percentage $=\left(\frac{\text { gain }}{\mathrm{CP}} \times 100\right) \%$
$=\left(\frac{3}{2} \times 100\right) \%$
$=150 \%$