Algebra
posted by Kate .
Can you help me set this up?
Mr. Smith could ride his 10speed bike 4.8 miles to his mom's house in 11 minutes. His return trip home took 14 minutes. The times are different due to there being a slight downhill slope on part of the trip to his mom's house. If Mr. Smith was able to ride his bike on a flat surface with no hills, how fast can he travel in miles/hour?
Thank you!!!!

the distance is the same
distance = speed * time
if the bike's flatland speed is b, and the drag caused by the uphills slope is s,
11/60 (b+s) = 4.8
14/60 (bs) = 4.8
b = 23.38 mph