Question

Consider this graph of a line that passes through the points (0,0) and (5,30)

Which equation represents the cost of a phone call, c, in cents, after m minutes, according to the payment plan?
A. c=1/6m
B. c=6m
C. c=1/30m
D. c=30m

Answer 1

B

Explanation:

Slope equals rise over run so the slope of this line is 30/5 or 6. That means for every minute calling you would have to pay 6 cents which is shown in the equation c=6m.

Answer 2

B!

the slope of the line represents the rate of the plan and can be calculated by using the change in y values divided by the change in x values of two points on the line. In this case, it would be easiest to pick 0 and 6 as y values, and 0 and 1 as x values. then,

slope = (6-0) / (1-0)
slope = 6/1
slope = 6

therefore the slope is 6 and the correct equation is B: c=6m