Find two positive numbers such that the sum of the first and twice the second is 120 and whose product is a maximum.

Question

anonymous · Answer

x + 2y = 120
2xy is a maximum
combinig 
P = 2xy =  x(120 - x)
differentiate
dP/dx =  120 - 2x = 0 for maxm/minm
so x = 60
second derivative =  -2   so this gives maximum 

60 + 2y = 120
so y = 30

your 2 positive numbers are 60 and 30

anonymous · Answer

Thanks! Can you help me with this one too?... Find the length and width of a rectangle that has an area of 968 square feet and whose perimeter is a minimum.

anonymous · Answer

sorry guy - its very late here in UK and i gotta get up early

anonymous · Answer

It's okayy