AlgebraMediumRatio changed by adding to one part
Algebra practice question
A jar holds red and blue beads in the ratio 3 : 5. If 12 red beads are added, the two colours are equal in number. How many blue beads are in the jar?
Answer: 30
Let red = 3k and blue = 5k. Then 3k + 12 = 5k → 2k = 12 → k = 6. Blue = 5(6) = 30.
Common wrong answers
- If you answered 6
- 6 is k, one 'part'.
- If you answered 12
- 12 is the number of beads added, not the blue count.
- If you answered 18
- 18 is the original number of red beads.
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