Answer:
16%
Step-by-step explanation:
say the percent decrease = x. Then
x/100 x 250 = 210.
x/2 x 5 = 210
x/2 = 210/5
x/2 = 42
x = 42 x 2
x = 84.....
BUT this is not the answer. We need 100-84=16 for the answer.
So the bike dropped 16%. Thank me later :)