Matt gets a $1,000 commission on a big sale. This commission alone raises his average commission by $150. If Matt's new average commission is $250, how many sales has Matt made?
Choose one.
A) 3
B) 4
C) 5
D) 6
E) 7
Let, Average Commission = x   No. of items sold = y   Total Commission = xy   New Commission = xy+1000   New Average = (xy+1000) / (y+1) = 150+x   i.e. (xy+1000) = (y+1)* (150+x)   i.e. (xy+1000) = (xy+x+150y+150)   i.e. (850) = (x+150y)   New Commission = 250 = 150+x   i.e. x=100   i.e. y = 5   New Sales = y+1 = 6   Answer: option 6
<result>D</result>
Matt gets a $1,000 commission on a big sale. This commission alone raises his average commission by $150. If Matt's new average commission is $250, how many sales has Matt made?