A company pays $30 per hour for up to 8 hours of work, and $45 per hour for overtime hours (hours beyond 8 hours). For up to 8 hours worked, the equation for total pay (y) for hours worked (x) is y = 30x. For over 8 hours worked, what is the equation for total pay (y) as a function of total hours worked (x)?
a) y = 8x
b) y = 30x
c) y = 45x
d) y = 30 + 45x