Question

by selling 12 oranges for 1 rupee a man loses 12%.how many for a rupee should he sell to gain 20%?

Answer 1

by selling 12 per rupee he loses 12%.

so the cost of 12 orange was

$= \frac{sp \times 100}{100 - loss\%} \\ = \frac{1 \times 100}{100 - 12} \\ \frac{100}{88}$

now he wants to gain 20%.

so the selling price should be

$= \frac{cp \times (100 + profit\%)}{100} \\ = \frac{ \frac{100}{88} \times (100 + 20)}{100} \\ = \frac{ \frac{100}{88} \times 120}{100} \\ = \frac{ \frac{12000}{88} }{100} \\ = \frac{12000}{88} \times \frac{1}{100} \\ = \frac{120}{88} \\ = 1.3636 \\ = 1.36$

hope it helps u