16Hit1600
AlgebraEasy–MediumDirect proportion

Algebra practice question

The quantity y is directly proportional to x, and y = 12 when x = 5. What is the value of y when x = 20?

Answer: 48

y = kx with k = 12/5. At x = 20: y = (12/5)(20) = 48.

Common wrong answers

If you answered 3
3 comes from 12 ÷ 4, dividing instead of multiplying.
If you answered 27
27 adds 15 to 12, treating the relationship as additive.
If you answered 60
60 is 12 × 5.

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