After riding her bike at 15 miles per hour, Anisa walked her bike the rest of the way at 4 miles per hour. If the total trip was 72 miles and took 7 hours, how many miles did she walk?

Question

After riding her bike at 15 miles per hour, Anisa walked her bike the rest of the way at 4 miles per hour. If the total trip was 72 miles and took 7 hours, how many miles did she walk?

Answer 1

Let x = time riding the bike

Then, 7 - x = time walking

Distance = (Rate)(Time)

So, 15x + 4(7 - x) = 72

11x + 28 = 72

11x = 44

x = 4 hours

She walked 4(7 - 4) miles = 12 miles

Answer 2

15b+w4=72

b+w=7

b=a

w=3