Hello could someone help me to solve this mats problem?
there are 42 students in a class. if there are 40% as many girls as boys, how many boys are there in the class?
a.12
b.17
c.20
d.25
e.30
Thanks for your help
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students in a class
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Vincelauret
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MartyMurray
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If there are 40% as many girls(G) as there are boys(B), then G = .4B.Vincelauret wrote:Hello could someone help me to solve this mats problem?
there are 42 students in a class. if there are 40% as many girls as boys, how many boys are there in the class?
a.12
b.17
c.20
d.25
e.30
So the total of boys and girls = B + .4B = 42.
Combine the terms on the left side to get 1.4B = 42.
Then B = 42/1.4 = 30.
Choose e.
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Vincelauret
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Thank you !!
now regarding to your solution I understand that I mistranslated the sentence in my own language....
I have to work harder!!!
now regarding to your solution I understand that I mistranslated the sentence in my own language....
I have to work harder!!!
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GMATGuruNY
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Alternate approach:Vincelauret wrote:Hello could someone help me to solve this mats problem?
there are 42 students in a class. if there are 40% as many girls as boys, how many boys are there in the class?
a.12
b.17
c.20
d.25
e.30
There are 40% as many girls as boys.
Thus:
G:B = 40:100 = 2:5.
Implication:
Of every 7 students, 2 are girls and 5 are boys, with the result that boys constitute 5/7 of the total number of students:
(5/7)(42) = 30.
The correct answer is E.
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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.
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Brent@GMATPrepNow
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If you're not sure how to approach a question, you can always test the answers.Vincelauret wrote: there are 42 students in a class. if there are 40% as many girls as boys, how many boys are there in the class?
a.12
b.17
c.20
d.25
e.30
ALSO, we can eliminate answers that do not yield an integer value for the number of girls.
Take answer choice A for example.
Answer choice A) 12
If there are 12 boys, then the number of girls = 40% of 12
In other words, there are 4.8 girls.
This makes no sense, so ELIMINATE A.
We can eliminate B for the same reason.
Answer choice C) 20
If there are 20 boys, then the number of girls = 40% of 20
So, there are 8 girls
This means the TOTAL number of students = 20 + 8 = 28
HOWEVER, the question tells us that there are 42 students.
ELIMINATE C.
.
.
.
Answer choice E) 30
If there are 30 boys, then the number of girls = 40% of 30
So, there are 12 girls
This means the TOTAL number of students = 30 + 12 = 42
PERFECT! The question tells us that there are 42 students.
So, the correct answer must be E
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
