Please help with this question

Dear student,​​​​​​

a) Upthrust = volume of block x density of water x g

                 = 15 x 10^-3 x 1000 x g
                 = 15 kgf
 
b) Since upthrust > weight
The block will float.
c) While floating, upthrust = weight of the block = 13.5 kgf

Regards