986:
a) 1/6*1/6 = 1/36 = 2,78%
b) (1/6)^2*6 = 1/6 = 16,67%
c) (3/6)^2 = (1/2)^2 = 1/4 = 25%
987.
a) 1 4, 4 1, 2 3, 3 2
P= (1/20)^2*4 = 4/400 = 1/100 = 1%
c) 6 1, 7 2, 8 3, 9 4, 10 5, 11 6, 12 7, 13 8 , 14 9, 15 10, 16 11,
17 12, 18 13, 19 14, 20 15
(1/20)^2 *15 = 15/400 = 3/80 =3,75%
b) 2 12, 12 2, 3 8, 8 3, 6 4 ,4 6
P= (1/20)^2* 6 = 6/400 = 3/200 = 1,5%
d) 1 5, 5 1, 2 10, 10 2, 3 15, 15 3, 20 4, 4 20
P= (1/20)^2*8 = 8/400 =2/100 = 2%