A phone company offers 2 monthly charge plans. In plan A , the customer pays a monthly fee of $25 and then another additional 9 cents per minute of use. In plan B, the customer pays a monthly fee of $32.60 and then an additional 7 cents per minute of use. For what amounts of monthly phone use will Plan a cost no more than plan b?

380 minutes

Explanation:

Given: Plan A : Monthly fee $25

                         Additional per minute charges = 9 cents

          Plan B = Monthly fee = $32.60

                         Additional per minute charges = 7 cents

The equation for cost usage under plan A will be,

X = 25 + 0.9 y

wherein y denotes the number of minutes consumed

Similarly, for Plan B, the equation would be,

X = 32.6 + 0.07 y

since total cost under the two has to be same at the same number of minutes.

Equating the two , we get,

25 + 0.09 y = 32.6 + 0.07y

⇒ 0.02y = 32.6 - 25

⇒ 0.02y = 7.6

⇒ y =

⇒ y= 380

Hence till the usage level of 380 minutes, Plan A will not cost more than Plan B.