44 it's above .5 so you round up!
He is wrong...
2 1/2 + 3 3/5 = 97/20
Simplified, I believe the answer is 4 17/20
I think the answer is substitution property of equality because you are substituting 9 for y as y=9.
You just keep subtracting 3 yo the previous number, so day one would be $82 and day three would be $79...etc. Day five would be $70 so sweet