50.3.1 problem 1
50.3.2 problem 2
50.3.3 problem 3
50.3.4 problem 4
50.3.5 problem 5
50.3.6 problem 6
50.3.7 problem 7
50.3.8 problem 8
50.3.9 problem 9
50.3.10 problem 10
50.3.11 problem 11
50.3.12 problem 12
50.3.13 problem 13
50.3.14 problem 14
50.3.15 problem 15
50.3.16 problem 16
50.3.17 problem 17
50.3.18 problem 18
50.3.19 problem 19
50.3.20 problem 20
50.3.21 problem 21
50.3.22 problem 22
50.3.23 problem 23
50.3.24 problem 24
50.3.25 problem 25
50.3.26 problem 26
50.3.27 problem 27
50.3.28 problem 28
50.3.29 problem 29
50.3.30 problem 30
50.3.31 problem 31