Question

Ravish bought 100 articles for Rs.4000. He sold 20 of them at a gain of 5%. At what gain per cent must he sell the remaining articles so as to gain 20% on the whole?

Answer 1

cost of 100 articles =4000/-
profit on whole=20%
(sp-cp/cp)100=20
(sp-4000/4000)100=20
sp-4000=20*40
sp-4000=800
sp=4000+800
therefore selling price of whole is 4800
for 80 articles 80*48=3840