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?

430

720

1150

1300

Question

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?

 430

 720

 1150

 1300

anonymous · Answer

a + b = 1150
 3a - 2b = 1300
 
2 * (a + b) + 3a - 2b = 2 * 1150 + 1300
 2a + 2b + 3a - 2b = 2300 + 1300
 5a = 3600
5a/5 = 3600/5
 a = 720
 
a + b = 1150
 720 + b = 1150
 b = 430

anonymous · Answer

A. 430