Question

Thoiba bought 150 toy guns for Rs 11250. He sold 30 of them at a gain of 8%. At what gain percent he sell the remaining so as to gain 12% on the whole?

Answer 1

150 toys=11250
1 toy= 11250/150=RS=7.5
he sold 30 toy=30×7.5=RS=51
remaining toys=150-30=120
he gain 12%on 120toys
gain%=gain/CP×100
price if 120 toys=120×7.5=900
so,
8%=x/900×100
8%=x\9
9 gone LHS
so,
9×8=x
then,
x=72