Customers of a phone company can choose between two service plans for long distance calls. the first plan has a $28 monthly fee and charges an additional \$0.09 for each minute of calls. the second plan has no monthly fee but charges $0.13 for each minute of calls. for how many minutes of calls will the costs of the two plans be equal?

Astudent is determining the influence of different types of food on the growth rate of spiders. she feeds one group of spiders two caterpillars twice a week. the other group received similarly-sized beetles twice a week. she records the amount of time required for individuals to reach sexual maturity. her hypothesis is that the spiders feeding on caterpillars will have a faster growth rate because caterpillars have a higher protein content compared to beetles. in this experiment, what is the dependent variable? spiders assigned to different feeding groups. time required to reach sexual maturity number of prey items fed twice a week. growth rates of each group.