Let p and m represent the numbers of miles in the plains and mountains, respectively.
.. p + m = 300 . . . . . . . the whole trip was 300 miles
time = distance/speed, so the trip time can be written as
.. p/90 + m/37.5 = 3 48/60
.. 5p + 12m = 1710 . . . . . . . . . . multiply by 450 to put in standard form
You can solve these two equations by any of several means. The variable p can be eliminated by subtracting 5 times the first from the second.
.. (5p +12m) -5(p +m) = 1710 -5*300
.. 7m = 210
.. m = 30
30 miles of the trip was through the mountains.
1/40 = .025, just multiply this by 21 and you have your answer
.525
Answer:
36 mph
Step-by-step explanation:
First, we have to find the unit rate of the money.
Since it's 15 dollars for each mile over the speed limit, divide 15 by 165.
The answer is 11, which means he was going 11 mph over the speed limit.
Add 11 to 25, and you get 36
In words: thirty two million, five thousand and eightin
expanded notation: 30 000 000 + 2 000 000 + +0 + 0 + 5000 + 0 + 0 + 8
