Suzette ran and biked for a total of 110 mi in 7 h. Her average running speed was 5 mph and her average biking speed was 20 mph. Let x = total hours Suzette ran. Let y = total hours Suzette biked. Use substitution to solve for x and y. Show your work. Check your solution.

(a) How many hours did Suzette run? 1.5 hours of running

(b) How many hours did she bike? 2 hours of biking

Guest Aug 21, 2019

#1**+3 **

x + y = 7 rearrange as y = 7 - x (1)

And using

Rate * Time = Distance we have that

5 * (x) + 20 (y) = 110 (2)

Sub (1) into (2) for y and we have that

5 * (x) + 20 ( 7 - x) = 110 simplify

5x + 140 - 20x = 110

-15x + 140 = 110 subtract 140 from both sides

-15x = - 30 divide both sides by - 15

x = 2 hours running

And 7 - x = 7 - 2 = 5 hours biking

CPhill Aug 21, 2019