algebra
posted by Bob J on .
Alan sold his bike to Dan making a 20% profit. Dan sold the bike to Carol for $180 which was a 25% profit for Dan. How much did Alan originally pay for the bike?
 A positive number is increased by 20%. This new number is now decreased by 20%. To obtain this final result the original positive number could be___.
a) left alone b) increased by 4% c) increased by 2% d) decreased by 4%
e) decreased by 2%

Dan to Carol:
C + 0.25C = $180.
1.25C = 180
C = $144. = Dan's cost.
Alan to Dan:
C + 0.2C = $144.
1.2C = 144
C = $120. = Alan's cost.
(N+0.2N)0.2(N+0.2N) =
N+0.2N0.2N0.04N = 0.96N.
0.96N/N = 0.96 = 96%.
96%  100% = 4% = 4% Decrease.