He has a commision of 11%, which means he gets 11% of the worth of the products he sold on top of his base salary of $400. 11% of $6050 is $665,50 so his total pay was $400 + $665,50 = $1,065.50
If the Sanchez family is using 2 3/4 (or 2.75) tubes of toothpaste and there are 12 months in a year, we use the equation above and get 33 as our answer.