A factory has three types of machines - A, B, and C - each of which works at its own constant rate. How many widgets could one machine A, one Machine B, and one Machine C produce in one 8-hour day?
(1) 7 Machine As and 11 Machine Bs can produce 250 widgets per hour
(2) 8 Machine As and 22 Machine Cs can produce 600 widgets per hour
Source: Veritas
OA: C
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
Work problem......Need help
This topic has expert replies
GMAT/MBA Expert
-
Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Sweet question!Mo2men wrote:A factory has three types of machines - A, B, and C - each of which works at its own constant rate. How many widgets could one machine A, one Machine B, and one Machine C produce in one 8-hour day?
(1) 7 Machine A's and 11 Machine B's can produce 250 widgets per hour
(2) 8 Machine A's and 22 Machine C's can produce 600 widgets per hour
Target question: How many widgets could one machine A, one Machine B, and one Machine C produce in one 8-hour day?
Statement 1: 7 Machine A's and 11 Machine B's can produce 250 widgets per hour
No information about Machine C
NOT SUFFICIENT
Statement 2: 8 Machine A's and 22 Machine C's can produce 600 widgets per hour
No information about Machine B
NOT SUFFICIENT
Statements 1 and 2 combined
Statement 1: 7 Machine A's and 11 Machine B's can produce 250 widgets per hour
Statement 2: 8 Machine A's and 22 Machine C's can produce 600 widgets per hour
Hmmm, I see that we're given info about 11 Machine Bs and 22 Machine Cs. Perhaps we might gain some useful information, if we create an EQUIVALENT statement such that Machines B and C produce the SAME number of widgets.
Take statement 2 and HALVE everything to get: 4 Machine As and 11 Machine Cs can produce 300 widgets per hour
Combine this new (equivalent) info with statement 1 to see we have two useful pieces of info:
7 Machine A's and 11 Machine B's can produce 250 widgets per hour
4 Machine As and 11 Machine Cs can produce 300 widgets per hour
So, if we ADD all of the machines we get:
11 Machine A's, 11 Machine B's and 11 Machine C's can produce 550 widgets per hour
Now divide everything by 11 to get: 1 Machine A, 1 Machine B and 1 Machine C can produce 50 widgets per hour
So, 1 Machine A, 1 Machine B and 1 Machine C can produce 400 widgets in 8 hours
Since we can answer the target question with certainty, the combined statements are SUFFICIENT
Answer = C
RELATED VIDEO
- Work questions: https://www.gmatprepnow.com/module/gmat ... /video/917
Brent Hanneson - Creator of GMATPrepNow.com
-
DavidG@VeritasPrep
- Legendary Member
- Posts: 2663
- Joined: Wed Jan 14, 2015 8:25 am
- Location: Boston, MA
- Thanked: 1153 times
- Followed by:128 members
- GMAT Score:770
Gotta love those three machine work problems. See here for another good one: https://www.beatthegmat.com/question-fro ... 11379.html
-
MartyMurray
- Legendary Member
- Posts: 2131
- Joined: Mon Feb 03, 2014 9:26 am
- Location: https://martymurraycoaching.com/
- Thanked: 955 times
- Followed by:140 members
- GMAT Score:800
There are, at least, two keys to getting this one.
- Realizing that you don't need values for A, B and C to have the value A + B + C - Seeing that you don't need the values of each variable in order to know the sum of the variables is useful for answering many GMAT questions.
For instance to answer a DS question asking for the value of 5x + 18y, a single statement saying that 20x + 72y = 107 is sufficient, because you can divide the statement equation by 4 to get the value of the expression in the question.
- Seeing that 22 is a multiple of 11 - Even if you weren't sure how to answer this question, as soon as you were to see that a couple of the variables have obviously related coefficients, you could suspect that C is the correct answer and start playing with the statements to see what results you might get.
Clues like that one are super useful for getting the right answers to DS questions.
- Realizing that you don't need values for A, B and C to have the value A + B + C - Seeing that you don't need the values of each variable in order to know the sum of the variables is useful for answering many GMAT questions.
For instance to answer a DS question asking for the value of 5x + 18y, a single statement saying that 20x + 72y = 107 is sufficient, because you can divide the statement equation by 4 to get the value of the expression in the question.
- Seeing that 22 is a multiple of 11 - Even if you weren't sure how to answer this question, as soon as you were to see that a couple of the variables have obviously related coefficients, you could suspect that C is the correct answer and start playing with the statements to see what results you might get.
Clues like that one are super useful for getting the right answers to DS questions.
Marty Murray
Perfect Scoring Tutor With Over a Decade of Experience
MartyMurrayCoaching.com
Contact me at [email protected] for a free consultation.
Perfect Scoring Tutor With Over a Decade of Experience
MartyMurrayCoaching.com
Contact me at [email protected] for a free consultation.
