How many kilometers did Bill run?

Question

In a week Mike ran 8km farther than Bill, while Pete ran 1km less than 3 times as far as Bill. If Pete ran 15km farther than Mike, how many kilometers did Bill run?

Answer 1

M = B+8

P = 3B-1

P = M+15 = (B+8)+15 = B+23

3B-1 = B+23

2B-1 = 23

2B = 24

B=12

Mike ran 20

Peter ran 35

Bill ran 12