Answer :
Finding x.
Suzette ran = x
Suzette biked = 4x
7 = x + 4x --) 7 = 5x --) 1.4 = x
Suzette ran for 1.4 hours
Finding y.
Quickest way is to use Suzette biked = 4x and substitute the x for 1.4 to find how much she biked.
4 x 1.4 = 5.6
1.4 + 5.6 = 7 hours the total time exercising
And the mileage adds up to.
5(1.4) + 20(5.6) = 119