Problem Solving

BTGModeratorVI wrote: ↑

Tue Jul 07, 2020 6:20 am

Luke drives the first 300 miles of a trip at 60 miles an hour. How fast does he have to drive, in miles per hour, on the final 200 miles of the trip if the total time of the trip is to equal 7 hours?

A. 60 mph
B. 90 mph
C. 100 mph
D. 120 mph
E. 200 mph

Answer: C
Source: Magoosh

At 60 mph, Luke would take 300/60 = 5 hours to cover 300 miles; thus, he has 7 – 5 = 2 hours to complete 200 miles. Thus, the average speed = 200/2 = 100 mph

Correct answer: C

Hope this helps!

-Jay
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BTGModeratorVI wrote: ↑

Tue Jul 07, 2020 6:20 am

Luke drives the first 300 miles of a trip at 60 miles an hour. How fast does he have to drive, in miles per hour, on the final 200 miles of the trip if the total time of the trip is to equal 7 hours?

A. 60 mph
B. 90 mph
C. 100 mph
D. 120 mph
E. 200 mph

Answer: C
Source: Magoosh

Luke drives the first 300 miles of a trip at 60 miles an hour.
Time = distance/time
So, travel time = 300/60 = 5 hours

How fast does he have to drive, in miles per hour, on the final 200 miles of the trip if the total time of the trip is to equal 7 hours?
Luke has already spent 5 hours driving the first 300 miles.
In order to complete the trip in a TOTAL of 7 hours, Luke must complete the next 200 miles in 2 hours

Speed = distance/ time
So the speed needed for the second leg = 200/2 = 100 mph

Answer: C

Cheers,
Brent

BTGModeratorVI wrote: ↑

Tue Jul 07, 2020 6:20 am

Luke drives the first 300 miles of a trip at 60 miles an hour. How fast does he have to drive, in miles per hour, on the final 200 miles of the trip if the total time of the trip is to equal 7 hours?

A. 60 mph
B. 90 mph
C. 100 mph
D. 120 mph
E. 200 mph

Answer: C

Solution:

The time for the first part of the trip is 300/60 = 5 hours. Thus, he has 7 - 5 = 2 hours to drive 200 miles. In order to achieve this, he has to drive at 200/2 = 100 mph.

Answer: C