SOLUTION: 1.A man drove a car at an average rate of speed of 45 miles per hour for the first 3 hours of a 7 hour car trip.If the average rate of speed for the entire trip was 53 miles per ho
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-> SOLUTION: 1.A man drove a car at an average rate of speed of 45 miles per hour for the first 3 hours of a 7 hour car trip.If the average rate of speed for the entire trip was 53 miles per ho
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Question 476752: 1.A man drove a car at an average rate of speed of 45 miles per hour for the first 3 hours of a 7 hour car trip.If the average rate of speed for the entire trip was 53 miles per hour,what was the average rate of speed in miles per hour for the remaining part of the trip?
(A)50
(B)55
(C)57
(D)59
(E)62
2.What is the average of (x+y)^2 and (x-y)^2?
(A)x+y/2
(B)xy
(C)x^2-y^2
(D)xy/2
(E)x^2+y^2
Please help and thank you so much for giving your time to help me with these problems.I really appreciate it. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! 1.A man drove a car at an average rate of speed of 45 miles per hour for the first 3 hours of a 7 hour car trip.
If the average rate of speed for the entire trip was 53 miles per hour,what was the average rate of speed in miles per hour for the remaining part of the trip?
:
let s = av speed for the remaining part of the trip
2nd dist drive time: 7 - 3 = 4hrs
:
Write a distance equation: dist = speed * time
:
1st dist + 2nd dist = total dist
45(3) + 4s = 53(7)
135 + 4s = 371
4s = 371 - 135
4s = 236
s =
s = 59 mph av speed on the remaining part of the trip
:
:
2.What is the average of (x+y)^2 and (x-y)^2?
Av =
;
Square the two expressions
Av =
;
combine like terms
Av =
:
cancel out 2
Av = x^2 + y^2
