Question

if the selling price of 10 pens is equal to the cost price of 14 pens find the gain percent

Answer 1

let the cost price of pen be x
and gain be y
then selling price is x+y
so A/q
10(x+y)=14x
10x+10y =14x
10y=4x
y=2x/5
since gain%=gain/cp × 100
so gain%=y/x×100
=2x/5x×100
=2/5×100
=2×20= 40%