From the condition, you have these two equations x - y = 400 (1) ("A salesman sold $400 more than the rest of the sales staff") x + y = 1600 (2) ("the sales total for the day was $1600") Add the equation (it is how the Elimination method works in this case). You will get 2x = 2000; hence, x = 1000 dollars. ANSWER. The rest of the staff sell for 1600-1000 = 600 dollars.