GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Alex drives to and from work each day along the same route. If he driv
[#permalink]
03 Jun 2022, 01:04
03 Jun 2022, 01:04
Expert Reply
1
Bookmarks
00:00
Question Stats:
93% (01:15) correct
6% (01:23) wrong based on 16 sessions
Hide Show timer Statistics
Alex drives to and from work each day along the same route. If he drives at a speed of 80 miles per hour on the way to work and he drives at a speed of 100 miles per hour on the way from work, which of the following most closely approximates his average speed in miles per hour for the round trip?
A. 80.0
B. 88.9
C. 90.0
D. 91.1
E. 100.0
A. 80.0
B. 88.9
C. 90.0
D. 91.1
E. 100.0
Part of the project: GRE QCQ & PS 3 Questions Every One DAILY Challenge - (2022)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: Alex drives to and from work each day along the same route. If he driv
[#permalink]
03 Jun 2022, 05:03
03 Jun 2022, 05:03
1
Bookmarks
Carcass wrote:
Alex drives to and from work each day along the same route. If he drives at a speed of 80 miles per hour on the way to work and he drives at a speed of 100 miles per hour on the way from work, which of the following most closely approximates his average speed in miles per hour for the round trip?
A. 80.0
B. 88.9
C. 90.0
D. 91.1
E. 100.0
A. 80.0
B. 88.9
C. 90.0
D. 91.1
E. 100.0
Part of the project: GRE QCQ & PS 3 Questions Every One DAILY Challenge - (2022)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
Let's assign a "nice" value to the distance Alex drives each way.
By "nice" I mean a value that works well with 80 mph and 100 mph
So, let's say the distance from home to work = 400 miles
Average speed = (TOTAL distance traveled)/(TOTAL travel time)
TOTAL distance traveled = 400 + 400 = 800 miles
TOTAL travel time = (travel time from home to work) + (travel time from work to home)
travel time = distance/speed
TOTAL travel time = (400/80) + (400/100)
= 5 + 4
= 9 hours
So, AVERAGE speed = 800/9
≈ 88.9
Answer: B
Cheers,
Brent
Re: Alex drives to and from work each day along the same route. If he driv
[#permalink]
03 Jun 2022, 08:30
03 Jun 2022, 08:30
1
Ans: (B) 88.9
Explanation :
Consider Alex travels 'D' distance from home to work and again the same 'D' distance from work to home .
So, Total distance = D+D = 2D.
Now, for time taken .
From home to work, t1=D/80;
and from work to home, t2= D/100.
Average speed=Total distance/total time taken.
= 2D/(D/80+D/100)
=88.9 miles/hour.
Posted from my mobile device
Explanation :
Consider Alex travels 'D' distance from home to work and again the same 'D' distance from work to home .
So, Total distance = D+D = 2D.
Now, for time taken .
From home to work, t1=D/80;
and from work to home, t2= D/100.
Average speed=Total distance/total time taken.
= 2D/(D/80+D/100)
=88.9 miles/hour.
Posted from my mobile device
