Hi Tammy;
x+x/2+(3/4)x=18
Let's multiply everything by 4. We are selecting 4 because this number is easily divisible by either 2 or 4...
4(x+x/2+(3/4)x)=18(4)
4x+(4x)/2+(4)(3/4)x=18(4)
4x+2x+3x=72
9x=72
x=8 inches=Jenny's share
x/2=4 inches=Demi's share
(3/4)x=6 inches=Drew's share
8 + 4 + 6=18
10/6/2013

Vivian L.