
Profit & Loss
I have got the following profit & loss problem:
Ron sold a watch to Sam at a gain of 10% & Sam sold it to Mike at a loss of 10%. If Mike paid $990 for it, find the price paid by Ron.
Can someone please help me out with this? Please show me the steps to do it.
Thanks

A x 1.1 =B
B x 0.9 = 990
so B = 990/0.9 = 1100
so A = 1100/1.1 = 1000
A is the price Ron bought the watch for, B is the price Sam bought the watch for (A + 10%, also written as A x 110% since A = 100% of A)
in the same way B x 0.9 (90%) is $990, the price paid by Mike
so Ron paid $1000 for the watch
Sam got ripped off
Mike made a good deal
you can thank me now kid