Question

A test is worth of 150 points and contains 70 questions. Some questions are worth 2 points, and some are worth 4 points

2x + 4y = 150

Answer 1

65 2 point questions, 5 4 point questions

Explanation:

write a system of equations:

let x be the number of 2 point questions and y be the number of 4 point questions

2x + 4y = 150

x + y = 70 (since there are 70 total questions)

x + y = 70

subtract x from both sides

y = -x + 70

substitute y = -x + 70 into 2x + 4y = 150

2x + 4(-x + 70) = 150

2x - 4x + 280 = 150

-2x = -130

x = 65

substitute x = 65 into x + y = 70

65 + y = 70

subtract 65 from both sides

y = 5