Question

buys pencils at 10 for Rs 3 and sells at 8 for
Rs 3. His gain percent is:
(b) 25
(d) 27
(e) None of these
Tips: Find the unit price first
(a) 20
(C) 30​

Answer 1

Answer:

c.p of one pencil=3/10

s.p of one pencil=3/8

profit sp-cp

$cp \: of \: one \: pencil = \frac{3}{10} \\ sp \: of \: one \: pencil = \frac{3}{8} \\ profit = sp - cp \\ \frac{3}{8 } - \frac{3}{10} = \frac{30 - 24}{80} = \frac{6}{80} = \frac{3}{40} \\ \\ gain\% = \frac{profit}{cp} \times 100 = \frac{3}{40 } \times \frac{10}{3} = \frac{10}{40} \\ \frac{1}{4} \times 100 = \frac{100}{4} = 25\%$

hope it's helpful