Is my working out correct (Simpson's Rule)

[Microsoft Word]

The trial paper i got the question from didn't include the answer, so i'm wondering if someone could look over my working. I really want to nail this topic so i can move on to something else.

It's Q26 e)
Link to paper: https://thsconline.github.io/s/?view=5318&id=0ByEFYhkkDQBKczhvcUlhekNGVEk&n=Normanhurst%20Boys%202016%20w.%20sol

Working out:
i) 20/3*(0+4(18)+32) + 20/3*(32+4(21)+0) = 1467m^2

ii) 5/3*(1467+4(1467)+1467) = 14670m^3
^ or should i just multiply the cross-sectional area by 15?

Thank you!

[Potatohater]

The trial paper i got the question from didn't include the answer, so i'm wondering if someone could look over my working. I really want to nail this topic so i can move on to something else.

It's Q26 e)
Link to paper: https://thsconline.github.io/s/?view=5318&id=0ByEFYhkkDQBKczhvcUlhekNGVEk&n=Normanhurst%20Boys%202016%20w.%20sol

Working out:
i) 20/3*(0+4(18)+32) + 20/3*(32+4(21)+0) = 1467m^2

ii) 5/3*(1467+4(1467)+1467) = 14670m^3
^ or should i just multiply the cross-sectional area by 15?

Thank you!

I) looks right to me
For ii) I thought you multiply I) by 15 but I'm not 100% sure, hopefully someone else can confirm

[Shadowxo]

I believe you multiply the area in i) by 15, as the volume is just the area x width and you've already approximated the area