Question

there are 45 questions on allison's english test. The multiple choice questions are worth 2 points each, and the short answer questions are worth 5 points each. The entire test is worth 120 points. Let x=multiple choice questions, and y=short answer questions. How many short answer questions are on the test?

Answer 1

x+y=45
2x+5y=120

  2(x+y=45)
  2x+5y=120
-___________
   -3y=-30
 y=10 is the answer