1. 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?
(b) how many hours did she bike?

Part a) Suzette ran 2 hours

Part b) Suzette biked 5 hours

Step-by-step explanation:

Let

x > total hours Suzette ran

y > total hours Suzette biked

we  know that

x+y=7

x=7-y > equation A

5x+20y=110 > equation B

Solve the system by substitution

substitute equation A in equation B and solve for y

5(7-y)+20y=110

35-5y+20y=110

15y=110-35

15y=75

y=5 hours

Find the value of x

x=7-5=2 hours

therefore

Suzette ran 2 hours and biked 5 hours

Check your solution

Her average running speed was 5 mph

so

Find the distance

Multiply the speed by the number of hours

5(2)=10 miles

Her average biking speed was 20 mph

so

Find the distance

Multiply the speed by the number of hours

20(5)=100 miles

Adds the two distances

10 +100=110 miles > is correct

597

step-by-step explanation: