Question 1202487
*[illustration photo.png].


Area of poster A = (x+8)(y+10)

area  printed  xy

Printed area =781.25

y = 781.25/x

A= (x+8)((781.25/x)+10)


A =781.25 +10x +6250/x +80

The critical point occurs when dA(total)/dx =0
 
dA/dx = 10 -6250/x^2 

10=6250/x^2

10x^2= 6250

x^2= 625

x = 25

y=35