a) 1100 = 12
100 = 4
111110 = 62
b) 201 = 19
111 = 13
10121 = 97
c) 4 = 100 (2), 11 (3)
9 = 1001 (2), 100 (3)
20 = 10100 (2), 202 (3)
32 = 100000 (2), 1012 (3)
