The function S (T, r) = 70 (T-90) (4- r) gives an ice cream shop's daily sales as a function of temperature T (in degrees° F) and rain r (in inches). Find Sr (80, 6) (include the appropriate units) and explain what it means.

The value of Sr (80, 6) is 1400 units.

The shop's daily sales when temperature is 80° F and rain is 6 inches.

Step-by-step explanation:

Given function that represents the daily sale,

S (T, r) = 70 (T-90) (4- r),

Where,

T = temperature (in degrees° F),

r = rain (in inches),

If T = 80° F, r = 6 inches,

S (80, 6) = 70 (80-90) (4- 6) = 70 (-10) (-2) = 1400 units

Hence, S (80, 6) represents the shop's daily sales when temperature is 80° F and rain is 6 inches.