SOLUTION: jake is on a 24-mile bike trip. He wants to average 10 miles per hour. He is halfway to his distination and has averaged 8 miles per hour. What must his average speed be on the las

Question 587747: jake is on a 24-mile bike trip. He wants to average 10 miles per hour. He is halfway to his distination and has averaged 8 miles per hour. What must his average speed be on the last part to complete on time
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Jake is on a 24-mile bike trip. He wants to average 10 miles per hour.
He is halfway to his destination and has averaged 8 miles per hour.
What must his average speed be on the last part to complete on time
;
Let s = the required speed to average 10 mph for the trip
:
write a time equation, time = dist/speed
:
+ =
Multiply by 40s
40s* + 40s* = 40s*
cancel the denominators
5s(12) + 40(12) = 4s(24)
60s + 480 = 96s
480 = 96s - 60s
480 = 36s
s = 480/36
s = 13 mph on the last half of the trip
:
:
Check, find the times.
+ =
1.5 + .9 = 2.4
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