Question

The width and length of a rectangle (in feet)are consecutive odd integers. If the length is increased by 5 feet, the area of the resulting rectangle is 60 square feet. What is the area of the original rectangle?
25 ft^2
30 ft^2
35 ft^2

Answer 1

Hello,

Let 's
2n-1 the width
2n+1 the length
Increasing by 5 feet , the length become 2n+6
The new area is (2n+6)(2n-1)=60
==>4n²+12n-2n-6=60
==>4n²+10n-66=0
Δ=10²+4*4*66=1156=34²
n=(-10+34)/8= 24/8=3 and an other value (-10-34)/8 negative excluded.

n=3 =>2n+1=7 and 2n-1=5
The first area was 7*5=35 (ft²)

Answer C