4 miles = 30 minutes
x miles = 45 minutes
(45)(4) = (30) (x)
180 = 30 x
devide both side by 30
x = 6
so he will run 6 miles in 45 minutes
Question 2:
9 taps = 4 hours
12 taps = x hours
(9)(x) = (12) (4)
9x = 48
devide both side by 9
x = 5.33333
so 12 taps will full the tank in 5.3333 hours