What is Kyle's fixed monthly salary in dollars?

Question

Kyle is a salesman.  His monthly earnings include a fixed monthly salary and a commission that is fixed percentage of his total sales for the month.  Kyle's total sales for the month of January were $15,000, and his total earnings for that month were $2,550.  Kyle's total sales for the month of February were $25,000, and his total earnings for that month were $3,050.  What is Kyle's fixed monthly salary in dollars?

Answer 1

let x=Kyle's fixed monthly salary

January: x+y%($15,000)=$2,550

February:x+y%($25,000)=$3,050

x=2550-(y/100)(15,000)

x=3050-(y/100)(25,000)

set the two equations equal

2550-150y=3050-250y

250y-150y=3050-2550

100y=500

y=5 %

x+(5%)(15,000)=2550

x+750=2550

x=2550-750

x=$1800, his fixed salary

x+(5%)(25,000)=3050

x+1250=3050

x=3050-1250

x=$1800 again