Abel, belle, and cindy have $408 altogether. belle has $7 more than cindy and $5 more than abel. how much does abel have.

Abel has 36 dollers because

7+5=12 
408-12=36

Abel has $135. You can solve this using system of equations.
You know that the money from A (Abel) + B (Belle) + C (Cindy) = $408
You also know that B = C + 7 and B = A + 5, because Belle has $7 more than Cindy and $5 more than Abel. Just switching the numbers around, C = B - 7 and A = B - 5. Now you can plug A and C back into the first equation to solve for B. 

(B - 5) + B + (B - 7) = 408
3B - 12 = 408
B = 140

We know that A = B - 5, so Abel has $140 - $5, which is $135.