For a system to be deadlock free ,
Sum of max need of processes < No. of processes + No. of resources ........ (i)
here System has allocated 2 resources to each process , and Total number of process = 101
so max need of processes = 101 * 2 = 202
let number of resources = R
so from (i) we get, 202 < 101 + R
101 < R
that means the minimum number of resources should be 102 .