Answer:
38.46%
Step-by-step explanation:
There are no names or marking that can make the calculator look different, so the order is not important. Then we should use a combination to solve this problem.
There are 40 calculators in one shipment, 37 of them good items and 3 of them are defect items. We need to choose 19 good calculators and 1 defect calculator. The number of ways to do that will be:
* 
= 37!
= 53017895700
The number of possible ways to choose 20 calculators out of 40 calculators will be:
= 
=137846528820
The chance will be: 53017895700/ 137846528820 = 0.3846= 38.46%
3, because negative numbers are less than positive numbers. Therefore, 3 is correct
It might be A but I'm not 100% sure inequalities was my worst thing I learned in algebra 2<span />
Basically given normal distribution we have to draw the bell curve with standard deviations which should look like(picture below) so draw something like that with center number being mean (3.53) and each positive standard deviation(SD) being + 0.2:
Ex 1 SD is 3.73, 2SD is 3.93, -1SD is 3.33
Now to solve the questions
A. If we know there’s 1000 gas stations and 3.93 is just 2 SD we can just refer to the picture below.
Basically because we’re finding the amount of values that are greater than that it should be percentage to the right of 2 SD. Which is 2.2% or 0.022 Then multiply that by the number of gas station.
So 0.022 * 1000 = 22.
B. This is basically the values between -2SD and 2 SD which is the percentage between them. Add 13.6 *2 + 34.1*2 = 95.2% or 0.952
Now multiply by 1000 * 0.952=952 gas stations.
C. For this one we just find percentage to the left of -1 SD or simpler just subtract half(the right half) and the percentage in 1 SD from 1 to find the remainder which is the value left of -1SD.
1-0.5 - 0.341 = 0.159
Now multiply by 1000 * 0.159 = 159 stations.
Hopefully this helps.
