27.1 problem 38.1
27.2 problem 38.2
27.3 problem 38.3
27.4 problem 38.4
27.5 problem 38.5
27.6 problem 38.6
27.7 problem 38.10 (a)
27.8 problem 38.10 (b)
27.9 problem 38.10 (c)
27.10 problem 38.10 (d)
27.11 problem 38.10 (e)
27.12 problem 38.10 (f)
27.13 problem 38.10 (g)
27.14 problem 38.10 (h)
27.15 problem 38.10 (i)
27.16 problem 38.10 (j)
27.17 problem 38.10 (k)
27.18 problem 38.10 (L)
27.19 problem 38.11