Question

a bookkeeper bought 2,000 exercise book distributed 200 books to the student from poor economic background as donation .he sold each remaining exercise book at rupees 10 more than the cost price of each and gained a percent 8%.
find the cost price of each exercise book​

Answer 1

Books left=2000-200=1800

ATQ

$\\ \sf\longmapsto 1800x+10=0.08x$

$\\ \sf\longmapsto 1800x-0.08x=-10$

$\\ \sf\longmapsto x(1800-0.08)=-10$

$\\ \sf\longmapsto x(1799.92)=-10$

$\\ \sf\longmapsto x=|\dfrac{10}{1799.92}|$

$\\ \sf\longmapsto x=0.005$

Now

$\\ \sf\longmapsto CP=0.005(2000)=10$