The following data reports the number of credits earned by a

The following data reports the number of credits earned by a student at a 4 year school. At the start of the semester, the student had earned 8 AP credits. Is the data linear? How do you know? Write an expression for the number of credits earned per semester.

Solution

Lets write the points in form ( semister no. , credits earned)

= ( 1 , 23) ; ( 2, 38) ; ( 3 , 53) ; ( 4 , 68)

change in credits with each semister = 38-23 = 53 -38 = 68-53 = 15

So, its a linear relation

Linear Expression : C = m*S + d

C = credits ; S = no. of semister ; d = constant

C = 15S +d : Find d using any point : (1, 23)

23 = 15 +d---> d = 8

C = 15*S+ 8