AlgebraEasy–MediumEquation from two descriptions of the same result
Algebra practice question
When a number is multiplied by 4 and the result decreased by 7, the outcome is the same as when the number is tripled and the result increased by 2. What is the number?
Answer: 9
Let the number be n: 4n − 7 = 3n + 2. Subtract 3n from both sides: n − 7 = 2, so n = 9. Check: 4(9) − 7 = 29 and 3(9) + 2 = 29.
Common wrong answers
- If you answered 5
- 5 comes from 4n − 7 = 3n + 2 solved as n = 7 − 2.
- If you answered 29
- 29 is the common outcome, not the number itself.
- If you answered -9
- −9 reverses the sign: n − 7 = 2 gives n = 9, not −9.
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