P (B₇₁,B₇₂)

P (B₇₃)

P (B₇)

0

0.1

0*0.1 = 0

0.03

0.1

0.03*0.2 + 0.1*0 = 0.006

0.27

0.3

0.27*0.5 + 0.3*0.03 = 0.144

0.42

0.4

0.42*0.9 + 0.4*0.3 = 0.498

0.28

0.1

0.28*1 + 0.1*0.72 = 0.352