Answer:
The probability that a call last between 4.2 and 4.9 minutes is 0.4599
Step-by-step explanation:
Let X be the length in minutes of a random phone call. X is a normal distribution with mean λ=4.2 and standard deviation σ=0.4. We want to know P(4.2 < X < 4.9). In order to make computations, we will use W, the standarization of X, given by the following formula
We will use 
, the cummulative distribution function of W. The values of are well known and the can be found in the attached file
We conclude that the probability that a call last between 4.2 and 4.9 minutes is 0.4599
Answer:
50 : 6 = x : 40 is the proportion
Step-by-step explanation:
50 : 6 = x : 40
x = 50 * 40 : 6
x = 333.33
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check
50 : 6 = 333.33 : 40
8.33 = 8.33
The answer is good
Answer:
427,000 = 4.27 * 
Step-by-step explanation:
Ron walks 1/2 mile in 10 minutes. There are six 10 minute intervals in an hour 60 divided by 10 is 6. So, therefore he can walk 1 mile in 20 minutes, 1/3 of an hour and a total of 3 miles per hour.
3 x 20 = 60.
Stevie walks 1/4 of a mile in 6 minutes, so that's 12 minutes to walk 1/2 mile. 60/12=5
Stevie can walk 5 half miles which transfers to 2 1/2 miles per hour.
Answer:
-1
Step-by-step explanation:
