Please help me with this word problem

Question

the phone company charges you a different rate for the first minute of a call than each additional minute. you see on your bill that a 12 minute call costs $2.03 and an 18 minute call cost $2.87. What are the costs of the first minute and each addtional minute?

 

 

 

 

 

 

its a linear combo/subsitution word problem. requirering 2 equations and 2 variables

Answer 1

If a = the first minute charge and b = the charge per minute after,

 

a + 12b = 2.03

a + 18b = 2.87

 

We can solve each for a.

 

a = 2.03 - 12b

a = 2.87 - 18b

 

Since a is equal to two different things, the two things are equal to each other.

 

2.03 - 12b = 2.87 - 18b

6b = .84

b = .14

 

a = 2.03 - 12(.14)

a = 2.03 - 1.68

a = .35

 

Boom.