sandy wrote:
Attachment:
#GREpracticequestion If s is a speed, in miles per hour, at which the energy.jpg
If s is a speed, in miles per hour, at which the energy used per meter during running is twice the energy used per meter during walking, then, according
to the graph above, s is between
A 2.5 and 3.0
B 3.0 and 3.5
C 3.5 and 4.0
D 4.0 and 4.5
E 4.5 and 5.0
Let's first familiarize ourselves with this diagram.
We'll start by examining what happens when
runners and
walkers travel at a speed of 4 miles per hour
The location of the
blue dot tells us that people RUNNING 4 mph use about
270 joules per metre
The location of the
red dot tells us that people WALKING 4 mph use about
190 joules per metre
270/
190 ≈ 1.4
So, when travelling at a speed of 4 mph, runners use about
1.4 times the energy that walkers use while travelling at a speed of 4 mph
We're looking for a speed at which runners use
TWICE the energy that walkers use while travelling at the same speed.
So we'll keep looking...
Now let's examine what happens when
runners and
walkers travel at a speed of approximately 2.7 miles per hour
The location of the
blue dot tells us that people RUNNING 2.7 mph use about
290 joules per metre
The location of the
red dot tells us that people WALKING 2.7 mph use about
145 joules per metre
290/
145 ≈ 2
So, when travelling at a speed of 2.7 mph, runners use about
2 times the energy that walkers use while travelling at a speed of 2.7 mph
Answer: A
Cheers,
Brent
_________________
Brent Hanneson – Creator of greenlighttestprep.comSign up for GRE Question of the Day emails