The three Math Idol judges have been eliminating contestants all day! The number of one-step equations and two-step equations who have been eliminated today is equal to 1150. If three times the number of one-step equations minus twice the number of two-step equations is equal to 1300, how many one-step equations eliminated today?

Question

dumbcow · Answer

x = 1 step
y = 2 step

--> x+y = 1150
--> 3x -2y = 1300

multiply 1st equation by 2 to cancel the "y" variable
then add equations together

---> 2(x+y =1150) --> 2x +2y = 2300
                                     3x  -2y  = 1300
                                    ---------------------
                                     5x         = 3600

Solve for x
x = 3600/5 = 720