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:
1
Step-by-step explanation:
If you ever divide a number by itself, it will be 1.
Answer:
$29.4
Step-by-step explanation:
I assume the question is based on simple interest since you didn't specify
Using simple interest
Simple interest=P×R×T
Where,
P=principal=$1470
R=interest rate=4%=0.04
T=time=6 months=0.5 year
Simple interest=P×R×T
=1470×0.04×0.5
=29.4
Interest earned=$29.4
Where is it? Don’t see it so uh