SOLUTION: A car traveled 1800 mi at a certain speed. If the speed had been 12 mph faster, the trip could have been made in 5 hours less. Find the speed.

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Question 1000197: A car traveled 1800 mi at a certain speed. If the speed had been 12 mph faster, the trip could have been made in 5 hours less. Find the speed.
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
RT=D basic uniform travel rates rule;

r%2At=%28r%2B12%29%28t-5%29=d, really this is two equations.

(1) Do you understand that combination equality?
(2) Can you solve the problem using it?

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

A car traveled 1800 mi at a certain speed. If the speed had been 12 mph faster, the trip could have been made in 5 hours less. Find the speed.
Let speed be S

Then hypothetical speed = S + 12

We then get the following TIME equation: 1800%2FS+=+1800%2F%28S+%2B+12%29+%2B+5

Solve for S to get a speed of highlight_green%2860%29 mph