Answer:
weak person: near the end of the ladder
strong person: nearer the center of the ladder
Step-by-step explanation:
The closer the strong person is to the center of mass of the ladder, the greater the fraction of the ladder's weight that person will carry. The weak person will feel less weight if the strong person is nearer to the center of mass.
For example, if the strong person is 3/4 of the ladder's length from the end where the weak person is, then the strong person will carry twice the weight the weak person is having to carry. (Assuming the mass is uniformly distributed.)