assembly line alpha starts and creates widgets at a rate of 25 w per hour. exactly one hour later, assembly line beta begins production at a rate of 30 w per hour. in how many minutes will the two assembly line have produced the same number of widgets?
1) 5
2) 25
3) 250
4) 300
5) 350
I like to know the formula for this and how to solve it (i reached different number)
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Brent@GMATPrepNow
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Assembly line alpha starts and creates widgets at a rate of 25 w per hour. Exactly one hour later, assembly line beta begins....mehrasa wrote:assembly line alpha starts and creates widgets at a rate of 25 w per hour. exactly one hour later, assembly line beta begins production at a rate of 30 w per hour. in how many minutes will the two assembly line have produced the same number of widgets?
A) 5
B) 25
C) 250
D) 300
E) 350
I like to know the formula for this and how to solve it (i reached different number)
So, in that 1 hour, assembly line alpha makes 25 widgets.
In other words, assembly line alpha has a 25-widget lead on assembly line beta.
Exactly one hour later, assembly line beta begins production at a rate of 30 w per hour
So, EVERY HOUR, assembly line beta makes 5 widgets more than assembly line alpha.
Since assembly line alpha has a 25-widget lead on assembly line beta, it will take 5 HOURS for assembly line beta to make up for that 25-widget deficit.
in how many MINUTES will the two assembly line have produced the same number of widgets?
5 HOURS = 300 minutes
Answer D
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talaangoshtari
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h w_alpha w_beta
1 25 0
2 50 30
3 75 60
4 100 90
5 125 120
6 150 150
So, from the moment that they work together, it takes 5 hour or 300 minutes for producing the same number of widgets.
1 25 0
2 50 30
3 75 60
4 100 90
5 125 120
6 150 150
So, from the moment that they work together, it takes 5 hour or 300 minutes for producing the same number of widgets.
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Brent@GMATPrepNow
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We can also solve this algebraically.assembly line alpha starts and creates widgets at a rate of 25 w per hour. exactly one hour later, assembly line beta begins production at a rate of 30 w per hour. in how many minutes will the two assembly line have produced the same number of widgets?
A) 5
B) 25
C) 250
D) 300
E) 350
Let t = number of HOURS that assembly line beta works
So, t + 1 = number of HOURS that assembly line alpha works
Also, assembly line beta's rate = 30 widget per hour
And, assembly line alpha's rate = 25 widget per hour
Now, start with a WORD EQUATION...
# of widgets that assembly line alpha produces = # of widgets that assembly line beta produces
Production = (rate)(time)
So, (25)(t + 1) = (30)(t)
Expand: 25t + 25 = 30t
Rearrange: 25 = 5t
Solve: t = 5
So, assembly line beta must work for 5 HOURS
5 hours = 300 minutes.
Answer: D
Cheers,
Brent
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GMATGuruNY
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An alternate approach is to PLUG IN THE ANSWERS. which represent the total time for Beta.mehrasa wrote:assembly line alpha starts and creates widgets at a rate of 25 w per hour. exactly one hour later, assembly line beta begins production at a rate of 30 w per hour. in how many minutes will the two assembly line have produced the same number of widgets?
1) 5
2) 25
3) 250
4) 300
5) 350
Since Alpha begins to work one hour earlier than Beta, Alpha's total time is 1 hour longer than Beta's total time.
When the correct answer choice is plugged in, Beta and Alpha will produce the same number of widgets.
Answer choices A and B seem way too small.
Of the remaining answer choices, start with the option in the middle (D).
Answer choice D: 300 minutes = 5 hours
At a rate of 30 widgets per hour, the number of widgets produced by Beta in 5 hours = r*t = 30*5 = 150.
At a rate of 25 widgets per hour, the number of widgets produced by Alpha in 6 hours = r*t = 25*6 = 150.
Success!
The correct answer is D.
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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
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