Question

A sells a bicycle to B at a profit of 20% and B sells it to C at a profit of 5%. If C pays 3780, what did A pay for it?

Answer 1

Let A pay x 
he sells to B at 1.2x
B sells it to C at 1.05*(1.2x) 
=1.26x 
1.26x =3780 
x=3000