Question

An electrician charges $50 to make a house call and $40 for each hour worked. if you have $200, can you afford a repair that takes 4 hours to complete?

Answer 1

No, it would cost $210. 
Each hour charges $40. 4 hours alone is $160.
On top of that, calling the electrician is a flat rate of $50. In total, it would cost $210. 

More mathematically, you could set up an equation. 

(Price) = $50 + $40 * (hours) 

Then plug in 4 hours 

price = 50 + 40*4
= 50+160
= 210