# Modeling situations as functions is common. Describe whether each description represents a function. Explain. a. The input is a day of the year. The o

Modeling
Modeling situations as functions is common. Describe whether each description represents a function. Explain.
a. The input is a day of the year. The output is the average temperature in Barcelona on that day.
b. The input is speed of a car. The output is the time it takes for a car moving constantly at that speed to travel 100 miles.
c. The input is a positive number. The output is a number whose absolute value is the input.
d. The input is a year. The output is the population of the United States during that year.

b) This is a function as for each value of speed, there is one value of time taken in hours. In fact, because of the data given, this function can be modeled by the equation: $$\displaystyle{f{{\left({x}\right)}}}=\frac{{100}}{{x}}$$