test40 #10

[dunkin77]

Hi,

I thought the answer should be B) but the answer sheet says E)...

Can anyone pls confirm?

[patrik.herzog]

x = side of the square

x^2 = (x+30)(x-20)
x^2 = x^2 -20x +30x -600
x^2 = x^2 +10x -600
10x = 600
x = 60

Hence, the answer is E

[dunkin77]

Oops, thanks.

I misunderstood the question that the area is 600.