How many hours

Question

two companies charge different rates, company A charges a flat fee of 55$ and 12.50$ for every hour, while company B charges 31$ and 18.50$ For every hour. How long until company A is cheaper than Company B?

Answer 1

For both companies, write an expression for the charge as a function of time, set them equal, and solve for the time.  That is the time when the charges meet.  At any time above that, the previously cheaper one becomes more expensive, and vice versa.

 

For C(t) with C in $ and t in hours,

 

C_A(t) = 12.50t + 55

 

C_B(t) = 31 + 18.50t

 

C_A = C_B ⇒

 

12.50t + 55 = 31 + 18.50t

 

Can you solve for t and finish from here?