$1,835.00
The equation to represent Fernando's weekly earnings is y = .05x + 250, where x is his sales. So when Fernando's sales total $4,000 he gets $450 that week.
y = .05x +250
y = .05(4,000) + 250
y = 200 + 250
y = 450
However, Fernando works 4 weeks this month, so take this answer and multiply it by 4. You get 1800. So Fernando makes $1800 this month, yet there's one holiday so add $35 to the $1800.