Answer:
12 km
Step-by-step explanation:
m = b + 8
p = 3b - 1
p = m + 15
p = m + 15....and m = b + 8....so we are gonna sub
p = b + 8 + 15
p = b + 23
b + 23 = 3b - 1
23 + 1 = 3b - b
24 = 2b
24/2 = b
b = 12 <==== Bill ran 12 km
m = b + 8
m = 12 + 8
m = 20 km....this is what mike ran
p = m + 15
p = 20 + 15
p = 35 km....this is what pete ran