2x - 4y = 8 2( x ) - 4y = 8 2( 3y-6 ) - 4y = 8 ... notice x has been replaced with 3y-6 2(3y)+2(-6) - 4y = 8 6y-12 - 4y = 8 2y-12 = 8 2y-12+12 = 8+12 ... add 12 to both sides 2y = 20 2y/2 = 20/2 ... divide both sides by 2 y = 10
If y = 10, then x = 3y-6 x = 3*10-6 ... replace y with 10 x = 30-6 x = 24
Put together, the solution is (x,y) = (24,10) which is why the answer is choice B
As a check, we can plug (x,y) = (24,10) into each equation x = 3y-6 24 = 3*10 - 6 24 = 30 - 6 24 = 24 ... true equation and similarly for the second equation as well 2x-4y = 8 2*24 - 4*10 = 8 48 - 40 = 8 8 = 8 ... true equation Both equations are true when (x,y) = (24,10) so the solution is confirmed
Your answer would be 36,000 because he gets 3000 every month and every month for a year he would get your answer which would be 3000×12 which equals 36,000
