Mr. gonzalez earns his living as a salary plus commission employee. his annual salary is $18,000. he makes 4% commission on all of his sales. mr. gonzalez wants to earn $60,000 this year. if his earnings are divided evenly throughout the year, how much in monthly sales would mr. gonzalez need to have?

To save ourselves from converting yearly to monthly wages more than needed, we will keep them in yearly form until the very last step.

If we know that Mr. Gonzalez's salary is 18,000, and that he wants to make 60,000, to find how much he needs to make through commission we should subtract his salary from his goal:
60,000 - 18,000 = 42,000

This shows us that Mr. Gonzalez needs to make $42,000 from commission. If he makes 4% commission on sales, then 4% times x (the amount of sales he will need over the year) will give us an equation for how much he needs to sell this year:
0.04 * x = 42,000
x = 42,000 / 0.04 = 1,050,000

Therefore, he will need to sell $1,050,000 worth of product over the course of a year. If we divide this answer by 12, we can find out the sales needed per month:
1,050,000 / 12 = 87,500

He will need $87,500 in monthly sales to make $60,000 per year.