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 840! If three times the number of one-step equations minus twice the number of two-step equations is equal to 870, how many one-step equations auditioned today?

Question

anonymous · Answer

wow this one again! 
where oh where does this come from?  get at least one a week.

anonymous · Answer

$$x+y=840$$$$3x-2y=870$$ does that look right?

callisto · Answer

If I interpret the question correctly .....
Let x = number of one-step equations 
      y = number of two-step equations 

''The number of one-step equations and two-step equations who have been eliminated today is equal to 840!''
=> x+y = 840  -(1)

''three times the number of one-step equations minus twice the number of two-step equations is equal to 870''
=> 3x - 2y = 870 - (2)

(1)x2 + (2)
2(x+y) + (3x - 2y) = 2(840) + 870 
All you need to do is to solve x.

anonymous · Answer

yeah looks good, but i still want to know where this question comes from. does everyone in the world take the same on line class?  and what the monkey is a "one step" equation?  and "math idol judges"?  puhleez

anonymous · Answer

I got is from my online class. 
So would that answer be 330, 510, 520, or 660?

callisto · Answer

It's better for you to solve it...

anonymous · Answer

Okay, thanks!

anonymous · Answer

solve 
$$x+y=840$$ for $y$ get 
$$y=840-x$$ substitute in to second equation with careful use of parentheses get 
$$3x-2(840-x)=870$$ and finally solve that linear equation for $x$

write what you think the answer is