Bill will receive 4% commission on $25,000, and that will equal $1,000.00 (multiply 25,000 x .04). You will then subtract the $25,000 from the $80,000, which will result in $55,000. Multiply the $55,000 by .06 and that will equal $3,300.00. Add $1,000 plus the $3,300 and you will find his commission is $4,300.00 for the total sale of $80,000.