What will the new dimensions be, in centimeters?

Question

Adaku has a rectangular photograph that is 20 centimeters wide by 30 centimeters long. She wants to reduce the area of the photograph by 264 square centimeters by decreasing the width and length by the same amount.

Answer 1

Let x = number of cm that the width is decreased

 

Area of new photo = Area of original photo - 264

 

(20-x)(30-x) = (20)(30) - 264

 

x² - 50x + 600 = 336

 

x² - 50x + 264 = 0

 

(x - 44)(x - 6) = 0

 

x = 44 or x = 6

 

x can't be 44 because then 20 - x would be negative

 

So, x = 6 cm

 

New dimensions:  14 cm by 24 cm