Question

Cost varies directly as time and the cost is $8 when the time is 2 hours, what is the constant of proportionality?

Answer 1

`k=4`

Explanation:

`"let C be cost and t be time then"`

`"the initial statement is "Cpropt`

`"to convert to an equation multiply by k the constant"`
`"of variation"`

`rArrC=kt`

`"to find k use the given condition"`

`"cost "=8" when "t=2`

`C=ktrArrk=C/t=8/2=4`

`rArr"constant of proportionality "=4`