Standard deviations of the four activities of the critical path are 1,2,4,2.
Standard deviation of this critical path = Sum of square root of variance of this corresponding critical path
Standard deviation of critical path 



Now we need to find the probability that the project will completed in 38 weeks given that its expected completion time is 40 weeks.
That is, we need to find P(X<38) :


Probability 
Thus the probability that the project will be completed in 38 weeks is 0.34.
There are four values, including the unknown value x. The sum of the four values is the given value of the mean, 11.5, multiplied by four. Let S be the sum of the four values. Then we can write:


x = 46 + 5 = 51
The answer is: The value of x is 51.
Answer:
12,345 tablets may be prepared from 1 kg of aspirin.
Step-by-step explanation:
The problem states that low-strength children’s/adult chewable aspirin tablets contains 81 mg of aspirin per tablet. And asks how many tablets may be prepared from 1 kg of aspirin.
Since the problem measures the weight of a tablet in kg, the first step is the conversion of 81mg to kg.
Each kg has 1,000,000mg. So
1kg - 1,000,000mg
xkg - 81mg.
1,000,000x = 81

x = 0.000081kg
Each tablet generally contains 0.000081kg of aspirin. How many such tablets may be prepared from 1 kg of aspirin?
1 tablet - 0.000081kg
x tablets - 1kg
0.000081x = 1

x = 12,345 tablets
12,345 tablets may be prepared from 1 kg of aspirin.
Answer:
The number of once is 9.1
The number of hundreds is 8.9
Step-by-step explanation:
Given as :
The total of digits having ones and hundreds = 900
The sum of digits = 18
Let The number of ones digit = O
And The number of hundreds digit = H
So, According to question
H + O = 18 .........1
100 × H + 1 × O = 900 ........2
Solving the equation
( 100 × H - H ) + ( O - O ) = 900 - 18
Or, 99 H + 0 = 882
Or , 99 H = 882
∴ H = 
I.e H = 8.9
Put the value of H in eq 1
So, O = 18 - H
I.e O = 18 - 8.9
∴ O = 9.1
So, number of once = 9.1
number of hundreds = 8.9
Hence The number of once is 9.1 and The number of hundreds is 8.9
Answer
Let x and y be the dimensions of the rectangle. If the perimeter is 40, we have

We can expression one variable in terms of the others as

Since the area is the product of the dimensions, we have

This is a parabola facing down, so it's vertex is the maximum:

So, the maximum is

And since we know that
, we have
as well.
This is actually a well known theorem: out of all the rectangles with given perimeter, the one with the greatest area is the square.