Answer:
The required probability is 0.55404.
Step-by-step explanation:
Consider the provided information.
The number of typographical errors on a page of the first booklet is a Poisson random variable with mean 0.2. The number of typographical errors on a page of second booklet is a Poisson random variable with mean 0.3.
Average error for 7 pages booklet and 5 pages booklet series is:
λ = 0.2×7 + 0.3×5 = 2.9
According to Poisson distribution: 
Where
is average number of events.
The probability of more than 2 typographical errors in the two booklets in total is:

Substitute the respective values in the above formula.



Hence, the required probability is 0.55404.
Answer:
a) 15.579
b) 39.019
Step-by-step explanation:
a) For the top 2% the z-value from the z table
z = 2.054
thus,
z =
here
X = 132
Mean = 100
thus,
2.054 =
or
σ = 15.579
b) Using tables, we get for Z = 0.89 the value of 0.8133 and for Z= 0.90 the value of 0.8159
By interpolation, values for 0.815 and we get Z=0.897
thus,
z =
here
X = 220
Mean = 185
thus,
0.897 =
or
σ = 39.019
Just subsititute the given values in the formula
x = 4 * 5 ( 7 + 9 ) = 320
The painting could be 5ft high and 12ft long, or it could be 4ft high and 15ft long, or it could also be 6ft high and 10 ft long