Answer:
0.865
Step-by-step explanation:
To solve for the probability we would be using the formula:
F(x) = 1 - e^−λx
Therefore, P(x > 2000) = F(x) = 1 - e^−λx
Mean = 1000 hours
λ = 1/mean = 1/1000 hours
x= 2000 hours
F(x) = 1 - e^−(1/1000)2000
F(x) = 1 - e^−2
= 0.8646647168
Therefore, the probability the the circuit will last at least 2000 hours = 0.865
there is no answer to this
So 400 stamps
African---> 100
Indian------> 1/10 x 400
= 40
European---> 400-40=360
1/3 x 360
= 120
so 120+40+100= 260
400-260
= 140 stams from US