SOLUTION
The mean is 4min
standard deviation is 1min
the z score is

where

then we have

The probability the call lasted less than 3 min will be
Therefore, the probability that (z < -1 ) is
[tex]\begin{gathered} Pr(z<-1)=Pr(0
Hence, the percentage of the calls that lasted less than 3 min is 16%
Answer:
2.50 or 2.5
Step-by-step explanation:
1/4=.25 so 25% of a number=5/8=0.625
So we multiply .625*4 to get the number. Since it's 25% and we want 100% to get it back to the original number
.625*4=2.50 or 2.5
The answer is B. You didn't mention compounding, so I have to assume that this is simple interest. The formula for simple interest is
<span>Interest = principal * interest rate expressed as a decimal * time in years. </span>
<span>$126 = $450 * X * 7. Now multiply $450 * 7 years = $3,150 </span>
<span>$126 = 3,150X </span>
<span>What has been done to the X? It was multiplied by $3,150. What is the opposite of multiplication? It is division. Remember that whatever we do to one side of the equal sign we must also do to the other side of the equal sign. </span>
<span>$126 = $3,150X </span>
<span>-------____---------- </span>
<span>$3,150__$3,150 </span>
<span>Any number over itself = 1. Now we have </span>
<span>.04 = X </span>
<span>To change a decimal to a percent move the decimal place two places to the right and add a percent sign. </span>
<span>.04 = 4$. The answer is B</span>