It will be mapped to block number 11 .
PA is divided as : 10 | 6 | 4
Division of PA : Tag = 10 bits , index = 6 bits , offset = 4 bits .
So for address 1200 take the 6 bits of index from PA i.e bits from block index and find the block number.
PA : Tag | Index | wo
0000000001 | 001011 | 0000
So, 001011 = 11
Alternative way is:
As one block has 16 addresses so address 1200 will be in 1200/16 =75 block number.
Now this block number will be mapped to 75%64 = 11.