|
|
GMAT 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.
18 Jan 2019, 01:10
Kudos
Bookmarks
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
78% (02:14) correct
22%
(02:34)
wrong
based on 216
sessions
History
Date
Time
Result
Not Attempted Yet
Working alone at a constant rate, Machine A can produce 15 widgets in 2 minutes. Working alone at a constant rate, Machine B can produce 20 widgets in 3 minutes. If the two machines start working at the same time, after how many minutes will Machine A have produced 40 more widgets than Machine B?
A 12
B 24
C 36
D 48
E 60
A 12
B 24
C 36
D 48
E 60
18 Jan 2019, 20:26
Kudos
Bookmarks
Working alone at a constant rate, Machine A can produce 15 widgets in 2 minutes.
Machine A rate: \(\frac{15 (widgets)}{2 (minutes)}\)
Working alone at a constant rate, Machine B can produce 20 widgets in 3 minutes.
Machine B rate:\(\frac{20 (widgets)}{3 (minutes)}\)
If the two machines start working at the same time, after how many minutes will Machine A have produced 40 more widgets than Machine B?
rate·time=work completed
We have the respective rates from above.
Machine A and B both work for the same time (we'll denote this time with x).
We know the work completed is a difference of 40
Machine A Rate·x - Machine B Rate·x=40 widgets
\(\frac{15 (widgets)}{2 (minutes)}·x - \frac{20 (widgets)}{3 (minutes)}·x=40 (widgets)\)
eliminate units for simplicity. Just remember x will be units of time
\(\frac{15x}{2}-\frac{20x}{3}=40\)
\(\frac{45x}{6}-\frac{40}{6}=40\)
\(\frac{5x}{6}=40\)
5x=240
x=48 minutes
D
Machine A rate: \(\frac{15 (widgets)}{2 (minutes)}\)
Working alone at a constant rate, Machine B can produce 20 widgets in 3 minutes.
Machine B rate:\(\frac{20 (widgets)}{3 (minutes)}\)
If the two machines start working at the same time, after how many minutes will Machine A have produced 40 more widgets than Machine B?
rate·time=work completed
We have the respective rates from above.
Machine A and B both work for the same time (we'll denote this time with x).
We know the work completed is a difference of 40
Machine A Rate·x - Machine B Rate·x=40 widgets
\(\frac{15 (widgets)}{2 (minutes)}·x - \frac{20 (widgets)}{3 (minutes)}·x=40 (widgets)\)
eliminate units for simplicity. Just remember x will be units of time
\(\frac{15x}{2}-\frac{20x}{3}=40\)
\(\frac{45x}{6}-\frac{40}{6}=40\)
\(\frac{5x}{6}=40\)
5x=240
x=48 minutes
D
General Discussion
Archit3110
Major Poster
18 Jan 2019, 08:09
Kudos
Bookmarks
Bunuel
rate for A = 15/2
rate for B = 20/3
solve using answer options we see
that at 48 mins ; A would have made 40 more widgets than B
15*48/2 = 360
20*48/3 = 320
IMO D
