Dear friends,

I am unable to solve the following problem. Will appreciate your help here. Thanks in advance.

The Purple Mobile Phone Company offers the following two pricing plans to customers. Plan A costs \$15/month, with calls at 25c/minute, while Plan B costs \$100/month with calls at 14c/minute. Find an equation that gives C, the cost in dollars, in terms of t, the call time in minutes per month for each plan.