Question

Linda was selling tickets for the school play. She sold 10 more tickets than children tickets and she sold twice as many senior tickets than children tickets. How do I solve for this?

Answer 1

Well, you have a system of two equations. Call senior tickets s, and children's tickets c. Then:
\[s = c+10\]
\[s = 2c\]
So, substitute 2c for s in the first equation:
\[2c=c+10\]
\[c = 10\]
Plugging that back in to one of the original equations, s=20. There's your answer.