Word problems algebra

Question

Yesterday, Susan went on a bike ride. Her average speed was 8 miles per hour. Today, she went on another ride, this time averaging 14 miles per hour. In the two days, she biked for a combined time of 11 hours. Write an expression for the combined total number of miles she biked in two days.

Answer 1

Distance = rate of speed times time traveled

d= rt

d = 8F + 14S F=hours biked on First day, S = hours traveled on Second day

F+S = 11, F=11-S, S=11-F

d = 8(11-S) +14S = 88-8S +14S = 88+6S

d = 88+6S

or

d= 8F +14(11-F) = 8F + 154 -14F = 154-6F

d = 154 -6F

88 < d < 154 total distance biked is between 88 and 154 miles