Answer:
Slow train: 68 mph
faster train: 68 + 21 = 89 mph
Step-by-step explanation:
Givens
The total distance is 785 miles
The rate of one train is r
The rate of the second train is r + 21
The time they travel that total distance of 785 miles is 5 hours.
Formula
d = r * t
r*5 + (r+21)*5 = 785 miles
Solution
5r + 5(r + 21) = 785 Remove the brackets on the left
5r + 5r + 105 = 785 Combine
10r + 105 = 785 Subtract 105 from both sides
10r = 680 Divide by 10
r = 680/10
r = 68
