Students

[rkhicha]

What is the ratio of the average (arithmetic mean) height of students in class X to the average height of students in class Y?

(1) The average height of the students in class X is 120 centimeters.
(2) The average height of the students in class X and class Y combined is 126
centimeters.

Am not entirely sure about the answer in the book

[gmatmachoman]

Afrer rephrase : Ax / Ay = ?

St 1 : Ax= 120. No data abt Ay. Insufficient

St 2 : Application of weigted average concepts :

Aw = (Nx *Ax + Ny * Ay) /(Nx +Ny)

Aw = 126 . No idea abt Ax/Ay/Nx/Ny is given Insufficient

Combining st 1 & st 2 :

still we dont know Nx & Ny. So we cant find Ay

Hey Ax : Average of X, Ay :Average of Y Nx: Number of students in X, Ny> Number of students in Y

Pick E

[kmittal82]

Hi,

this question has been answered here as well, with a nice pointer for these types of questions:

https://www.beatthegmat.com/average-t23670.html

[gmatmachoman]

Hi,

this question has been answered here as well, with a nice pointer for these types of questions:

https://www.beatthegmat.com/average-t23670.html

Okay Mittal, if the question would have asked what is the ratio of students in class & class Y what will be ur answer??

[kmittal82]

Hi,

this question has been answered here as well, with a nice pointer for these types of questions:

https://www.beatthegmat.com/average-t23670.html

Okay Mittal, if the question would have asked what is the ratio of students in class & class Y what will be ur answer??

I don't understand your question here gmatmachoman, could you repost it please?

[ymach3]

hi gmatmachoman


Okay Mittal, if the question would have asked what is the ratio of students in class & class Y what will be ur answer??

even then, the answer would be E because i dnt have S(y) in this case...


let me know if i am wrong.