When student weighing 45 kgs left a class, the average weight of the remaining 59 students increased by 200g. What is the average weight of the remaining 59 students?

Since the student who left weighed 45 kgs, the total weight of all 60 students (including the student who left) is 59x + 45.

When the student left, the average weight of the remaining 59 students increased by 200g (or 0.2 kgs), so we can set up the equation:

59x + 45 = 60(x - 0.2)

Simplifying the equation, we get:

59x + 45 = 60x - 12

Solving for x, we get:

x = 57

So, the correct answer is: 57