 Hello and welcome to the session. In this session we are going to discuss the following question and the question says that Samuel got a new phone plan. The following graph shows the cost for several minutes. First, write the point 1R where R is unit rate. Second, what does the point 5, 7.5 represent on the graph? Third, what does other pair 5, 7.5 mean with respect to the point 1R? Let us proceed to the solution. In this question we have given the graph showing the cost of the call for several minutes. On x-axis we are having minutes and on y-axis we are having cost and sense. As we can see the graph is of a straight line passing through the origin that is 00 also ratio of each ordered pair is given by 1.5 upon 1 which is equal to 7.5 upon 5 and is equal to 9 upon 6 and we observe that each ratio is equal to 1.5 which is constant as the graph is of a straight line passing through origin and ratio of each of the ordered pair is constant. So we can say it is a proportional relationship also unit rate will be given by y upon x that is 1.5 by 1 which is equal to 1.5. So here R is the unit rate and cost of call per minute will be 1.5 cents. So we have 1R as 1, 1.5. So we can say the point 1R where R is the unit rate is given by 1, 1.5. Next we shall find out what does the point 5, 7.5 represent on the graph. In ordered pair 5, 7.5 the x coordinate is 5 and the y coordinate is 7.5. Here we see that the x coordinate is given by 5 and the y coordinate is 7.5. It means for a 5 minute call the cost is 7.5 cents. Next we shall see what does ordered pair 5, 7.5 mean with respect to the point 1R. Now we know that the unit rate is 1.5. It means the cost per minute is given by 1.5 cents which means with increase in 1 minute the cost increases by 1.5 cents. Now let us consider the ordered pairs 1R that is 1, 1.5 and 5, 7.5. Here we see change in y by change in x will be equal to change in y means 7.5 minus 1.5 and change in x will be 5 minus 1 which is equal to 6.4. It shows that when we move 4 units horizontally from point 1 to point 5 then we move 6 units vertically from point 1.5 to 7.5. It means when we increase the time by 4 minutes the cost is increased by 6 cents. This completes our session. Hope you enjoyed this session.