Homework fag here and it's kwiz time
>>32694
Principle of Archimedes
Calculate the volume of the raft, determine the weight of maximal displaced water (1 kg per l, that is, 1 dm^3), the difference between this and the weight of the raft (52 kg) is the solution.
https://en.wikipedia.org/wiki/Archimedes%27_principle
>>32694
find the boyant force of the raft and set it equal to the gravitational force excerted by you unknown mass. then solve for the mass.