Cost varies directly as time. The cost is $8 when the time is 2 hours. What is the constant of proportionality?

1/4
16
6
4

k = 4

Step-by-step explanation:

Given cost c varies directly as time t, then the equation relating them is

c = kt ← k is the constant of variation

To find k use the condition c = 8 when t = 2, then

8 = 2k ( divide both sides by 2 )

4 = k

The constant of proportionality is 4.

Step-by-step explanation:

let C be cost and t be time then the initial statement is C ∝  t

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

⇒ C=kt

to find k use the given condition

cost  =8 when t=2

C  =  k t  ⇒  k  =  C/ t =  8 /2  = 4

⇒  constant of proportionality = 4

the first one, all those points on the line just make a strait line.

i did it myself and i got 4.2 (b) hope its right

step-by-step explanation: