Mr. Martin’s math test, which is worth 100 points, has 29 problems. Each problem is worth either 5 points or 2 points.Let x be the number of questions worth 5 points and let y be the number of questions worth 2 points.x + y = 29, 5x + 2y = 100How many problems of each point value are on the test?10 problems worth 5 points and 25 problems worth 2 points14 problems worth 5 points and 15 problems worth 2 points16 problems worth 5 points and 13 problems worth 2 points15 problems worth 5 points and 13 problems worth 2 points
Accepted Solution
A:
x + y = 29......multiply by -2 5x + 2y = 100 ----------------- -2x - 2y = - 58 (result of multiplying by -2) 5x + 2y = 100 ----------------add 3x = 42 x = 42/3 x = 14 <==== there were 14 five-point questions
x + y = 29 14 + y = 29 y = 29 - 14 y = 15 <=== there were 15 two-point questions