For this case we have to:
Let "x" be the variable that represents the number of grapes Godswill ate on Monday, so we have:
- Monday:

- Tuesday:

- Wednesday:

- Thursday
![: [(x + 6) +6] + 6 = x + 18](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fjmr6ew1it9sysd8l9manpulxsbneejrcs.png)
- Friday:
![{[(x + 6) +6] +6} + 6 = x + 24](https://img.qammunity.org/2020/formulas/mathematics/middle-school/f184et3telt7pvzn5a22vflppvrx6blkq2.png)
Finally we have the following expression:

We add similar terms:

So, on Monday he ate 8 grapes
Answer:
On Monday he ate 8 grapes.