Average rate of change is defined by (y^-y)/(t^-t) where the ^ means the final(so final y and final t)
So you'd do (8.75-2.75)/(12-4) which is 6/8 which is 3/4 of a dollar per week
A) Only Zoe is correct.
2,899 rounded to the nearest hundredth would be 2,900