Answer:
a) The probability of selling less than 100 gallons (x≤1) is P=0.16.
b) The mean number of gallons is M=80 gallons.
Step-by-step explanation:
The probability of selling x, in hundred of gallons, on any day during the summer is y(x)=0.32x, in a range for x from [0;2.5].
The probability of selling less than 100 gallons (x≤1) is then:

The mean number of gallons can be calculated as:

Graph the equation in a graphing calculator or in the table in a regular calculator and look for the zero on the x axis and the y axis
Answer:
The answer to the first question is 7.15
The answer to the second question is 1.73