a test is worth 150 points and contains 70 questions. some questions are worth 2 points and some are worth 4 points. how many are worth 2 and how many are worth 4

Answer 1

a + b = 70 -----> a = 70 - b

2a + 4b = 150

2(70 - b) + 4b = 150

140 - 2b + 4b = 150

2b = 10

b = 5

a = 70 - 5

a = 65