AlgebraMediumThree pieces of a ribbon
Algebra practice question
A ribbon 240 centimetres long is cut into three pieces. The second piece is twice as long as the first, and the third piece is 20 centimetres longer than the second. What is the length, in centimetres, of the first piece?
Answer: 44
Let the first piece be x: the second is 2x and the third is 2x + 20. Then x + 2x + 2x + 20 = 240 → 5x = 220 → x = 44.
Common wrong answers
- If you answered 52
- 52 comes from 5x = 260, adding the 20 instead of subtracting it.
- If you answered 88
- 88 is the second piece (2 × 44).
- If you answered 108
- 108 is the third piece (88 + 20).
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