let's call their parts w,m and s
if will paid 1/3, then m+s=2w (they paid 2/3, which is twice as much as will did)
Now, we know that:
Micah and Sue paid in the ratio 2:3.
this means the 3m=2s
and m=2/3s
Again:
m+s=2w
and we substitute m:
2/3s+s=2w
5/3s=2w// multiply both sides by 3
5s=6w
we also know that s=w+6 (from the last sentence) so we substitute:
5(w+6)=6w
5w+30=6w
30=w
so, Will paid 30, Sue paid 36 (six more than him), Mike paid 24 (24:36 is the same ratio as 2:3, you can check this by dividing both 24 and 36 by 12: you have 2 and 3)
and the total was 30+36+24=90.
