Final answer:
The original weight of the wood before drying is calculated using the formula: original weight = dry weight / (1 - moisture content). With a dry weight of 60 kg and 40% moisture content, the weight before drying is 100 kg.So, the correct option is: d) 100 kg
Step-by-step explanation:
If the weight of a piece of wood after drying was found to be 60 kg, and the percentage moisture content was 40%, we need to calculate the weight before drying.
To do this, we can consider the formula: original weight = dry weight / (1 - moisture content), where the moisture content is expressed as a decimal. Therefore, the original weight of the wood before drying is 60 kg / (1 - 0.40) = 60 kg / 0.60 = 100 kg. Hence, the correct answer is (d) 100 kg.