Based on the graph shown to the right, whose phones cost varies directly with the amount of time spent talking? a.) mark’s only b.) nikiya’s only c.) both mark’s and nikiya’s

B. Nikiya's only

Step-by-step explanation:

Mark’s cost does not vary directly with time spent talking because the cost of 0 hours is not 0 dollars

For Nikiya’s plan, the value of the constant of variation is 15

which represents Nikiya’s cost per hour

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.