so let organize
The salesperson earns $60 a week , plus $4.50 for every sale they make, so
60 + 4.50
By the end of the week they want at least $250 earned, so we need to know how many sales they need to make so they can have $250 by the end of the week.
60 + 4.50n = 250
-60 -60
4.50n = 190
/4.50 /4.50
n=42.222
Since sales can be decimals let's round it to 43. Not 42 because then they will have less than $250. So, they need to atleast make 43 sales.