The graph of the line represents the cost of renting a kayak. Write a linear function in the from y= mx + b represents the relationship of the total Cost ,c, of renting a kayak for t hours?

The correct answer is: c = 3t + 7

Total cost = c
Time for which kayak is rented = t hours
In the graph, when t = 1 , c = 10 and t = 3 , c = 16
Using two – point form, equation of the line is
(y – y₁) = m (x – x₁)  where  m = 

m = 

         =  = 3
Now,  equation of the line is (c – c₁) = m (t – t₁)
(c – 10) = 3 (t – 1)
c – 10 = 3t – 3
c = 3t – 3 + 10
c = 3t + 7