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5 kg of apples cost 30 yuan: price of 8 kg?
At a fruit shop, 5 kg of apples cost 30 yuan in total. At the same unit price, how much do 8 kg of apples cost?
Answer
48
Step-by-step
- 30 ÷ 5 = 6Find the unit price first (reduce to one)
- 6 × 8 = 48Unit price × quantity
Why it works
The price per kilogram is the total cost divided by the mass; with the unit price unchanged, the total cost grows in proportion to the mass.
Common mistakes
- Dividing 30 by 8 to get the price per kilogram.
- Adding 6 to 30 instead of multiplying the 6 yuan per kilogram by 8 kg.