A rectangle is 12 feet long and 5 feet wide. If the length of the rectangle is increased by 25% and the width is decreased by 20%, what is the change in the area of the rectangle?

Answer 1

The old area is 12*5=60
the new area is

12*1.25 * 5*1.20 = 90

So, the increase is 90-60 = 30

As for % increase, note that you now have

12*1.25 * 5*1.20 = (12*5)(1.25 * 1.20) = (12*5)(1.50)

That is a 50% increase

Answer 2

Are you positive this is correct?