Answer:
Step-by-step explanation:
d = r * t
Let the time at 59 miles / hour be t
59*t + 57* (4.5 - t) = 259.5 Remove the brackets
59*t + 256.5 - 57*t = 259.5 Combine the left
2t + 256.5 = 259.5 Subtract 228 from both sides
2t = 259.5 - 256.5 Combine
2t = 3 Divide by 2
t = 1.5
So he spent 1.5 hours going at 59 miles per hour
He spent 4.5 - 1.5 = 3 hours going 57 miles per hour.
