What percent above the cost price of an item should a shopkeeper mark his goods so that after allowing a discount of 30%, he still gains 10%?

Answer 1

40%

Answer 2

If he marks up r%, then

(1+r)c*.70 = 1.1c
1+r = 1.1/.7
r = 1.1/.7-1 = 0.57 = 57% or 4/7

Check:
cost = 14
1.57*14 = 22
22*.7 = 15.4 = 14 * 1.10