Holly has a rectangular garden that measures 12 m wide by 14 m long. She wants to increase the area to 255 m2 by increasing the width and length by the same amount. What will be the width (shorter dimension) of the new garden?

A.
14 m wide

B.
17 m wide

C.
15 m wide

D.
16 m wide

Question

Holly has a rectangular garden that measures 12 m wide by 14 m long. She wants to increase the area to 255 m2 by increasing the width and length by the same amount. What will be the width (shorter dimension) of the new garden?
 
 A.
14 m wide
 
 B.
17 m wide
 
 C.
15 m wide
 
 D.
16 m wide

imstuck · Answer

I got this one for you!  Figure out the Old area to be 12 x 14.  In order to increase the new area by the same length on each of the sides, you have to add x to each of them:  12 + x, 14 + x.  Now you multiply these together and et them to equal the new area of 255.  Here's what we have so far, after FOILING.  255 = x^2 + 26x - 87.  Factor this and solve for x.  The x is 3 or - 29, and since the distance can never be negative, x = 3.  So the new dimensions are 15 and 17.  C is your answer.