Answer:
1534 pudding cups
Explanation:
The volume of the tub with dimensions 5 ft × 5 ft × 2.5 inches is ...
(5×12 in)×(5×12 in)×(2.5 in) = 9000 in³
The volume of 3.25 fluid ounces is (231/128)×3.25 in³, so the number of pudding cups required to fill the "hot tub" is ...
(9000 in³)/(231/128×3.25 in³) ≈ 1534.47 . . . pudding cups
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If the tub is 2.5 ft deep, not 2.5 inches, then the number of pudding cups required is 12 times this amount, or ...
12×1534.47 ≈ 18,413.59 ≈ 18,414 . . . pudding cups
This is because the tub volume is not 9000 in³, but is 12 times that amount, or 108,000 in³.