Question

A farmer bought 100 hens for rs 400,sells 20 of them at a gain of 5%.At what gain % must he sell the remaining hens so as to get 20% gain on the whole?

Answer 1

CP of 1 hen=400/100=4Rs
Profit percentage=profit/CP=`(SP-CP)/(CP)`
`5/100=(SP-80)/80`
SP=84 for 20 hens
`20%=((SP)/100-(CP)/100)/((CP)/100)`
`SP=80+400=480Rs`
Gains percentage on remaining=`(396-320)/320*100`
=23.75%.