According to the given conditions 

in first case block is completely inside water by putting 10 kg in it means density of block will be less than that of water

according to the law of floatation we know that 

wt. of solid = upthrust

so 10g + AL(0.01)Dg = AL(0.01)dg

in second case

AL(0.01)Dg = A[L-2](0.01)dg

substracting 2nd eq. by 1st eq. we will get A = 1/2

now initial lenght in start is not provided by you, if it is given then calculate V = AL(0.01)

In thid question d and D are densities of liquid and solid, A and L are area of bottom of block and its length in cm.   0.01 is for converting cm. into m.