Answer:
The correct answer is D) (-2, -1)
Step-by-step explanation:
In order to solve this system of equations, start by multiplying the entire first equation by 2. Then add the two equations together. This will get the y's to cancel and allow you to solve for x.
-4x + 2y = -10
3x - 2y = 12
---------------------
-x = 2
x = -2
Now that we have the value for x, we can find y by plugging the x value into either equation.
-2x + y = -5
-2(2) + y = -5
-4 + y = -5
y = -1
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%
#1 shop A would be cheaper