SOLUTION: With the old 55m.p.h. speed limit it used to take Shawn 2 more hours to drive to visit his parents' home than it does with the new 65m.p.h. limit. How ong does it take him to driv

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Question 114861: With the old 55m.p.h. speed limit it used to take Shawn 2 more hours to drive to visit his parents' home than it does with the new 65m.p.h. limit. How ong does it take him to driver there now?
Answer by solver91311(24713) About Me  (Show Source):
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Let the time to make the trip at 65 mph be t. Then the time to make the trip at 55 mph is t + 2.

So one expression for the distance using d=rt is 65t. And another expression for the same distance is 55%28t%2B2%29. Since these expressions are for the same distance, we can say that they are equal.

65t=55%28t%2B2%29
65t-55t=110
10t=110
t=11. It takes 11 hours to drive there now.

Check: 65%2A11=715, so the trip must be 715 miles. The trip at 55 must have taken 11 + 2 or 13 hours, so check 55%2A13=715.