10,000 x[1 - 0.20]^N < 3,000
10,000 x 0.8^N < 3,000 Divide both sides by 10,000
0.8^N < 0.3 Take the log of both sides
N > Log(0.3) / Log(0.8)
N > 5.4 - Years after which the value of the motorcycle will be less than $3,000.
