SOLUTION: if there are 30 questions on a test. Each question is worth either 2 or 3 points. The total is 78 points. How many of each type is on the test? How do i write this equation and

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Question 752550: if there are 30 questions on a test. Each question is worth either 2 or 3 points. The total is 78 points. How many of each type is on the test?
How do i write this equation and solve?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = the number of questions worth two points each.
The remainder (that's 30-x) are worth three points each.
The sum of these is 78 points.
So we can write the equation:
2x+%2B+3%2830-x%29+=+78 Solve for x.
2x+%2B+90-3x+=+78 Combine the x's.
-x+%2B+90+=+78 Subtract 90 from both sides.
-x+=+-12 so...
x+=+12
There are 12 two-point questions and 18 three-point questions.