Let A, B, C,... X, Y, Z be positive numbers such that AC = B, BD = C... XZ = Y. Given that A+B = 1988, find the maximum value of Y+Z?
Let A = x and C = y
Then B = xy
D=1x
E=1xy
F=1y
G = x
H = xy
I = y
So we see that this is a sequence with a period six. So A = Y and B = Z.
Given A+B = 1988, so maximum value of Y+Z = 1988.