Your teacher is giving you a test worth 100 points containing 40 questions. There are 2-point and 4-point questions on the test. How many of each type are there.

Question

dealing w/-subst. and elimin.

Answer 1

let number of 2 pointers be x, then number of 4pointers is y

so x+y = 40
2x + 4y = 100

take it from there