The average weight of 12 crewmen in a boat is increased by 1/3 kg, when one of the crewmen whose weight is 55 kg is replaced by a new man. What is the weight of that new man ?

Answer: Option D

According to the question,
Average weight of the 12 crewman increased by = $$\frac{1}{3}$$ kg
∴ Total increase in weight
$$\begin{array}{rl}& =12\times \frac{1}{3}\\ & =4\text{ kg}\end{array}$$
Weight of old man = 55 kg
Weight of new man = 55 + 4 = 59 kg