siddreal wrote:

chetan2u wrote:

PrakharGMAT wrote:

Hi Experts

Please have a look on my approach. I have created 3 equations-

1) (Sum) / N = X

2) When a new student of weight 80 is added the equations become

(Sum +80)/ (N+1) = X-1

3) When the students gain weight by 110. In this case the students have put on more weight so we just need to add 110 in the sum.

(Sum + 110) / N= X+4

After solving these equations I am getting X=102 which is not correct.

I know, I am missing something.

Can you please assist.

Thanks and Regards,

Prakhar

hi,

i find the approach to be OK BUT the highlighted portion has to be N+1 and not N..

Try putting that and check your answer

I made these 2 equations as well with N+1 as said by chetan2u, but was not able to get the value of 'x'.

Please show the solution here.

Sum/N = X

Sum = NX

(Sum +80)/ (N+1) = X-1

(Sum + 80) = (N+1)*(X - 1)

NX + 80 = NX - N + X - 1

X - N = 81 ........ (i)

(Sum + 110) / (N+1) = X+4

Sum + 110 = (X + 4)(N + 1)

NX+ 110 = NX + 4N + X + 4

4N + X = 106 ......... (ii)

Solve (i) and (ii)

4X - 4N = 324

4N + X = 106

5X = 430

X = 86

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Karishma

Veritas Prep GMAT Instructor

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