Question

If the two trains are 540 miles apart after 3 hours, what is the rate of the westbound train?

Do not do any rounding.

Answer 1

Givens

T = 3 hours for both

d = 540 miles total

r_east = r

r_west = r - 20

Equation

r_east * T + r_west = 540

Sub and solve

r*T + (r - 20)*T = 540

r*3 + (r - 20)*3 = 540

3*r + 3r - 60 = 540 Add 60 to both sides and combine like terms on the left.

6r = 540 + 60

6r = 600 Divide by 6

r =600/6

r = 100

Conclusion

East bound train's rate = 100 miles per hour

West bound train's rate = 100 - 20 = 80 miles / hour.