Answer:
y = 22.5x
worked 28 hours
Explanation:
First find out what they make in 1 hour (rather than 40)
you can do this by 900 / 40 which gives you 22.5
this means for every hour worked, they get $22.50
so you can make the equation of y = 22.5x
try finding the hours worked by division
630/ 22.5 = 28
plug 28 into your equation to check
y = 22.5 ( 28 )
y = $630
hope this helps