Answer:
(The whole question can be seen in the Attachment)
(a) Plan A , $6
(b) 160 minutes, Plan B
Explanation:
<h2>
(a) </h2>
If Chris makes 40 mins of calls for the month, which plan costs less?
In the graph, it can clearly be seen that for 40 mins, Plan A costs $4 while Plan B costs $10. So Plan A costs less.
How much less does it cost than the other plan?
Plan B cost $10 while Plan A costs $4. So Plan A costs $10-$4=$6 less than plan B
<h2>(b)</h2>
For what number of minutes both plans have the same cost?
We can see from the graph that both plans A and B coincide at 160 mins where the cost of both plans become $16
If the time spent on calls is more than this amount, which plan cost less?
Plan B costs less after time spent on call exceeds 160 mins.