A marathon runner drinks one bottle of sports drink for every 3 miles he runs, and the number of bottles he drinks as a function of the number of miles he runs can be described by the function B(m) = m/3. The cost of a bottle of sports drink is $1.25, and the cost in dollars of the sports drink that the runner consumes as a function of the number of bottles he drinks can be described by the function C(b) = 1.25b. If the runner runs 24 miles, how much does the sports drink he consumes cost?

a) $30

b) $3.75

c) $1.75

d) $10

Julius
Jan 18, 2018

#1**+2 **

B(m) = m/3 ...this means... number of bottles = m / 3

C(b) = 1.25b ...this means... cost = 1.25( number of bottles )

So... cost = 1.25( m / 3 )

cost = 1.25( 24 / 3 ) = 1.25( 8 ) = 10

hectictar
Jan 18, 2018

#2**+3 **

The number of 3 mile 'sets' that he runs is 24/3 = 8 'sets' or 8 bottles of sports drink.

8 bottles x $1.25 / bottle = $10.00

ElectricPavlov
Jan 18, 2018