The answer to your question is 12
Plan 1 because she spends 435.88 more if she goes with plan 2
In an hour there are 60 minutes.
6:38 PM + 22minutes = 7 PM
From 7 PM to 7:23 PM there are 23 minutes
So, (23 + 22) minutes = 45 minutes.
410.3ft^3. is correct
volume of the sphere with 3ft radius :
volume of the sphere with 5ft radius:
difference
good luck