A test has twenty questions worth 100 marks in total. There are two types of…
2017
A test has twenty questions worth 100 marks in total. There are two types of questions. Multiple choice questions are worth 3 marks each and essay questions are worth 11 marks each. How many multiple choice questions does the exam have?
Answer: B. 15 — Let x be the number of multiple choice questions. Then the number of essay questions is 20 − x. Equation: 3x + 11(20 − x) = 100 Expand: 3x + 220 − 11x = 100…
- A.
12
- B.
15
- C.
18
- D.
19
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Correct answer: B
Let x be the number of multiple choice questions.
Then the number of essay questions is 20 − x.
Equation: 3x + 11(20 − x) = 100
Expand: 3x + 220 − 11x = 100
Combine like terms: −8x + 220 = 100
Rearrange: −8x = −120
Solve: x = 15
Check: 15 × 3 + 5 × 11 = 45 + 55 = 100, so there are 15 multiple choice questions.