Suppose Lakeside Marina charges a $35 rental fee for a boat in addition to charging $15 per hour. The linear function is modeled by f(x)=15x + 35, where f(x) represents the total cost of renting the boat, and x represents the number of hours the boat was rented. What is the cost of renting the boat for 3 hours? A.

$80

B.

$10

C.

$10

D.

$50

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.