SOLUTION: David knew he made a mistake when he calculated that Gilda walks 123 miles to the station. Read through David's calculations: Using d = rt, the distance is the same, but the rat

Question 1029836: David knew he made a mistake when he calculated that Gilda walks 123 miles to the station. Read through David's calculations:
Using d = rt, the distance is the same, but the rate and time are different.
If Gilda misses the train, it means the time t needs 7 more minutes so d = 3(t + 7).
If she gets to the station 5 minutes early means the time t can be 5 minutes less so d = 4(t - 5).
3(t + 7) = 4(t - 5)
3t + 21 = 4t - 20
t = 41
d = rt, so d = 3(41) = 123
Find David's mistake in his calculations. Include the correct calculations and solutions.
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
he solved for t = 41.
the equation of d = rt is not the one he needs, however.
he needs to go back to the two equation he used to solve for t = 41.

d = 3(t+7) becomes d = 3(41+7) becomes d = 3(48) becomes d = 144.
d = 4(t-5) becomes d = 4(41-5) becomes d = 4(36) becomes d = 144.

the correct distance is 144.

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