GMAT Paper Tests
\(A\) can complete a project in 20 days and \(B\) can complete the same project in 30 days. If \(A\) and \(B\) start working on the project together and \(A\) quits 10 days before the project is completed, in how many days will the project be completed?
A. 18 days
B. 27 days
C. 26.67 days
D. 16 days
E. 12 days
OA A
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
\(A\) can complete a project in 20 days and \(B\) can
This topic has expert replies
-
GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Let the job = 60 units.AAPL wrote:GMAT Paper Tests
\(A\) can complete a project in 20 days and \(B\) can complete the same project in 30 days. If \(A\) and \(B\) start working on the project together and \(A\) quits 10 days before the project is completed, in how many days will the project be completed?
A. 18 days
B. 27 days
C. 26.67 days
D. 16 days
E. 12 days
Rate for A alone = w/t = 60/20 = 3 units per day.
Rate for B alone = w/t = 60/30 = 2 units per day.
Since A quits 10 days before the project is completed, B works alone for 10 days.
Work completed by B alone in 10 days = r*t = 2*10 = 20 units.
Remaining work = 60-40 = 40 units.
These 40 units were completed by A+B working together (before A quit).
Combined rate for A+B working together = 3+2 = 5 units per day.
Time for A+B to complete 40 units = w/r = 40/5 = 8 days.
Total time = time for B alone + time for A+B together = 10+8 = 18 days.
The correct answer is A.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
GMAT/MBA Expert
-
Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7247
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We are given that A can complete a project in 20 days and B can complete the same project in 30 days. Thus, the rate of A is 1/20 and the rate of B is 1/30. Since A quits 10 days before the project is completed, we can let t = the time in days worked by B, and thus, (t - 10) = the time in days worked by A. To determine t, we calculate the work done by A and the work done by B, using the work formula: work = rate x time.AAPL wrote:GMAT Paper Tests
\(A\) can complete a project in 20 days and \(B\) can complete the same project in 30 days. If \(A\) and \(B\) start working on the project together and \(A\) quits 10 days before the project is completed, in how many days will the project be completed?
A. 18 days
B. 27 days
C. 26.67 days
D. 16 days
E. 12 days
OA A
work of A + work of B = 1
(1/20)(t - 10) + (1/30)(t) = 1
(t - 10)/20 + t/30 = 1
Multiplying the entire equation by 60, we have:
3t - 30 + 2t = 60
5t = 90
t = 18
Answer: A
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
