SOLUTION: Noah is trying to qualify for a race. A driver needs to complete 8 laps of a seven-mile track at an average speed of 105.66 mph to qualify. Noah has already completed the first thr

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Question 329411: Noah is trying to qualify for a race. A driver needs to complete 8 laps of a seven-mile track at an average speed of 105.66 mph to qualify. Noah has already completed the first three laps. His average speed so far is ninety-two mph. What must his average speed be for the rest of the race to qualify?
Any help with this will be greatly appreciated
Thanks!!!
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A-H be the speed for each of his qualifying laps.
For the first 3 laps,
%28A%2BB%2BC%29%2F3=92
A%2BB%2BC=276
.
.
.
The average for all 8 laps,
%28A%2BB%2BC%2BD%2BE%2BF%2BG%2BH%29%2F8%3E=105.66
.
276%2BD%2BE%2BF%2BG%2BH=845.28
.
D%2BE%2BF%2BG%2BH=569.28
.
.
So then the average for the last 5 laps must be,
%28D%2BE%2BF%2BG%2BH%29%2F5%3E=113.856mph