kvcpk wrote:Thanks for all your replies guys..

I wanted to confirm the rule that I was using.. I am answered now..

Thank you!!

It can be solve in a number of ways.

Method 1
y = 25x - x^2 = x(25-x)

Sum of x and 25-x is constant. It will attain a max value at x = 25-x mpliy x = 12.5

Method 2
First derivative = 0 as gmatmachoman did it.

Method 3
y = 25x - x^2 = (25/2)^2 - (25/2 - x)^2
y to be max, (25/2 - x)^2 should be zero; imply x = 12.5

It is dependent on the comfort level of individuals.

winnerhere wrote:Y = 25x - x^2

Find the value of X , for which Y attains maximum value.

How to proceed with this question

Thanks in Advance,
Sai

Calculus
d/dx=25-2x, optimum is x=12.5
d^2/dx^2=-2 and we attain max Y at 12.5