Variables x and y are non-zero integers. If x = 2y3 /z what happens to

Question

Variables x and y are non-zero integers. If x = 2y^3 /z what happens to z when x is halved and y is doubled? 
 (a) z is not changed
 (b) z is halved
 (c) z is doubled
 (d) z is multiplied by 4
 (e) z is multiplied by 16

Thanks!

CrackverbalGMAT · Answer

Given that x =  \frac{2y^3}{z}

z =  \frac{2y^3}{x}

x becomes x/2 and y becomes 2y

Substituting these in the above equation, we get  \frac{2*(2y)^3}{\frac{x}{2}}  =  \frac{2 * 8y^3 * 2}{x}  = 16 * \frac{2y^3}{x}  = 16z

or z is multiplied by 16

Option E

Arun Kumar

WBogey · Answer

Hi  CrackVerbalGMAT ,
I think there is a typo in your answer. Please let me know if I'm because I think this changes the answer as well...

Greetingss

CrackverbalGMAT · Answer

Heloo WBogey. There was an error in terms of copying the question while solving it. I took it as  y^3  instead of  2y^3 , and have edited the same.

There is no change in the answer.

y becomes 2y and not 4y, because the question says  2y^3  and not  (2y)^3 .

If the question was  (2y)^3 , y would double and become 4y, but not in this case above.

Hope this helps.

v12345 · Answer

x = \frac{2y^3 }{z}

z = \frac{2y^3 }{x}

x is halved and y is doubled
New  z = \frac{2(2y)^3 }{x/2} = 16*\frac{2y^3 }{x} = 16z

Hence, OA is (E).

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Variables x and y are non-zero integers. If x = 2y3 /z what happens to

Prep Toolkit

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