The initial volume of water poured into a bag of dry soil was 50ml and the amount that drained through was…

Analyze the question: Water was poured onto dry soil. Some drained through, and the rest was retained by the soil. We need the percentage of the original water that the soil retained.

Concept: Water retained = water added - water drained. Percentage water content (as this question frames it) = (water retained ÷ water added) × 100.

Solution:

1. Water retained = 50 ml - 35 ml = 15 ml
2. Percentage = (15 ÷ 50) × 100 = 30%

Checking the other options:

• 46.7% comes from 15 ÷ 35 × 100 = 42.9%, which doesn't match, so it is not a valid route. It might come from a different incorrect combination.
• 25% and 20% don't come from any sensible calculation using these numbers.

Answer: D. 30.0

Tip: In these soil-water questions, first find what the soil kept (water added minus water drained). Then divide by the original volume added, unless the question says otherwise. Always write out the subtraction first, because it prevents the common mistake of using 35 as your answer base.