Answer:
$87.50
Step-by-step explanation:
If they split the money 1:7 this means they divided it into 8 portions. (Because 7+1=8). So do $100/8=12.5.
(You never specified who got 1 portion and who got 7, so I will assume Alex got the 7)
Let's say Jill got the 1 portion, she gets $12.50.
Let's say Alex got the 7 portion, he got $12.50 x 7 = $87.50