Answer:
Step-by-step explanation:
Given that a machine produces defective parts with three different probabilities depending on its state of repair.
condition Good order Wearing down Needs main Total
Prob 0.8 0.1 0.1 1
Defective 0.02 0.1 0.3
Joint prob 0.016 0.01 0.03 0.056
a) 0.016
b) total = 0.056
c) If not defective from needs maintenance
Prob for not defective = 
From machine that needs maintenance = 0.07
So reqd prob = 
The answer is c. If the answer is wrong i am sorry
So the tree is 40 ft and then the shadow is 30 so then do 40 -30 = 10 ft difference so then for the second tree do 20 + 10 = 30 ft because the 10 ft difference so the answer is 30 ft tall