Equation

by **Vinsgmat** Tue Jun 10, 2008 7:13 pm

15. A rectangular circuit board is designed to have width w inches, perimeter p inches, and area k square inches. Which of the following equations must be true?
(A) w^2 + pw + k = 0
(B) w^2 - pw + 2k = 0
(C) 2w^2 + pw + 2k = 0
(D) 2w^2 - pw - 2k = 0
(E) 2w^2 - pw + 2k = 0

Source is from a quantititative aptitude book. Answer is not given[/img][/code]

by **aryan** Wed Jun 11, 2008 6:24 pm

Lets us assume length = l
w*l = k (area) or l=k/w
2w+2l=p (perimeter)
substitute l in second equation...
2w+2k/w=p is same as 2w^2-pw+2k=0 (E) :)

by **rfernandez** Fri Jun 13, 2008 4:15 am

Nice solution!