A tire company manufactures 50 tires an hour with its current staff. The company can make 10 extra tires per hour for every extra worker it hires. Which of the following equations represents this relationship mathematically, with x being the number of extra workers hired and y being the number of tires produced?
a.x= 10 +50Y
b.x= 50+10y
c.y= 10 +50x
d.y= 50+ 10x