In the expression above, if yn ≠ 0, what is the value of m?

Question

m=\frac{\frac{3}{n}}{\frac{2}{y}+\frac{1}{2y}}

(1) y = 3n/2
(2) n = 3/2

Bunuel · Answer

Similar question from OG: https://gmatclub.com/forum/in-the-expre ... 44341.html

garcmillan · Answer

The most important thing to realize in this question is that it is asking by the value of m, so we need to cancel both y and n so that the given option is SUFFICIENT.

1) y = 3n/2 ---> Let's substitute y by 3n/2 in the given equation:

m=(3/n)/(2/y+1/12y) --->(3/n)/(4/3n+2/36n) ---> (you can keep simplyfing this formula from here, but before doing that you just need to realize that in the numerator we have a fraction with n in the denominator and in the denominator we have a fraction with n in the denominator. That means that regardless of the numbers that the equation will have, at the end, n wil be cancelled ---> SUFFICIENTE

2) n = 3/2 ---> Don't even start substituting because we have no info about y so m will depend on y ---> NO SUFFICIENT

OPTION A

Note that it is very important in DS problems to save most of the time by not doing extra steps. You should quickly relaize in option 1 that n would cancel

Please hit the kudos button if this post helped you

anbknaga · Answer

m=\frac{\frac{3}{n}}{\frac{2}{y}+\frac{1}{2y}}

=>  m=\frac{3*(2y^2)}{n*(4y+y)}  =  m=\frac{3*(2y^2)}{n*(5y)}  
=>  m=\frac{6y}{5n}

Statement 1: y = 3n/2

Substitute this in the above eqn.,

=>  m=\frac{6*1.5*n}{5n} 
=>  m=\frac{9}{5}

so Statement 1 is SUFFICIENT.

Statement 2: n = 3/2

Substituting this in the eqn.,

=>  m=\frac{6*y}{5*1.5}

we don't know the value of y to determine m.

so Statement 2 is INSUFFICIENT.

Therefore the answer is  A

Kinshook · Answer

Given:   m=\frac{\frac{3}{n}}{\frac{2}{y}+\frac{1}{2y}}

Asked:  In the expression above, if yn ≠ 0, what is the value of m?

m=\frac{\frac{3}{n}}{\frac{2}{y}+\frac{1}{2y}} = \frac{6y}{5n}

(1)  y = \frac{3n}{2} 
 \frac{y}{n} = \frac{3}{2} 
 \frac{6y}{5n} = \frac{3}{2} * \frac{6}{5} = \frac{18}{10} = 1.8 
SUFFICIENT

(2)  n = \frac{3}{2} 
Value of y is unknown
NOT SUFFICIENT

IMO A

Bunuel · Answer

Video Explanation

Y16-ydvWyFo

In the expression above, if yn ≠ 0, what is the value of m?

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