Help please ! Please

15, 8, 25 The teacher payed 0.40 per book.

Step-by-step explanation:

4/10 = 2/5 Simplify the 4/10 to find the unit rate.

15: 2/5 = 6/x Set up your proportion.

    2x   =30 Cross multiply

    /2      /2 Divide both sides by 2 to isolate x

     x     =15

8: 2/5 = x/20 Set up proportion

   40  =5x Cross multiply

    /5     /5 Divide both sides by 5 to isolate x

     8  =x

25: 2/5 = 10/x Set up proportion

      2x  =50 Cross multiply

       /2     /2 Divide both sides by 2 to isolate x

        x   =25

Graph: y=mx+b To graph, you will need to use y=mx+b format

           y= 2/5 x+2 2/5 is your unit rate. Your rate changes every 2 books bought. To graph, start at (0,2) and go up 2 and to the right 5, plot. Continue moving up 2 and to the right 5 to graph.

The teacher payed 0.40 per book because 2/5 simplifies to 0.40.