Answer:
6.25x + 2d
Step-by-step explanation:
6.25x = The Hourly Pay
2d = Bonus Pay
Add them to find the total:
6.25x + 2d
Not addition, since

and 0 doesn't belong to the set.
Not subtraction, since

.
It is closed under multiplication. The set appears to contain all non-zero multiples of 3.
Not division, since dividing some of the numbers results in rationals which do not belong to the set.
What other operations are you supposed to consider?
Answer:
N=3/5
Step-by-step explanation:
(1/5)/N=1/3
N=(1/5)/(1/3)
N=(1/5)(3/1)
N=3/5
V=hπr^2
(15π(3.5^2)ft^3)(55/100)(7.5gal/ft^3)≈2381.23 gal (to nearest hundredth of a gallon)