find the length of each person's sandwich?

an 18inch long sandwich was purchased &
Jenny cuts the sandwich so that Demi gets 1/2 of what Jenny gets and Joel gets 3/4 of what Jenny gets.

1 answer

de = .5 je
jo .75 je

je + de + jo = 18

1 je + .5 je + .75 je = 18
2.25 je = 18
je = 8
then
de = 4
and
jo = 6