Answer:
it is not possible you cannot divide by zero
Answer:
a) 20.16; b) 20.49 and 21.51
Step-by-step explanation:
We use z scores for each of these. The formula for a z score is
.
For part a, we want the 20th percentile; this means we want 20% of the data to be lower than this. We find the value in the cells of the z table that are the closest to 0.20 as we can get; this is 0.2005, which corresponds with a z score of -0.84.
Using this, 21 as the mean and 1 as the standard deviation,
-0.84 = (X-21)/1
-0.84 = X-21
Add 21 to each side:
-0.84+21 = X-21+21
20.16 = X
For part b, we want the middle 39%. This means we want 39/2 = 19.5% above the mean and 19.5% below the mean; this means we want
50-19.5 = 30.5% = 0.305 and
50+19.5 = 69.5% = 0.695.
Looking these values up in the cells of the z table, we find those exact values; 0.305 corresponds with z = -0.51 and 0.695 corresponds with z = 0.51:
-0.51 = (X-21)/1
-0.51 = X-21
Add 21 to each side:
-0.51+21 = X-21+21
20.49 = X
0.51 = (X-21)/1
0.51 = X-21
Add 21 to each side:
0.51+21 = X-21+21
21.51 = X
In order for this to be a model of exponential growth, the b term must be greater than 1.
If the b term is between 0 and 1, then it becomes a model for exponential decay as the number will continue to get smaller and smaller for every value of x. Greater than one will continue to grow and therefore be an exponential growth model.
I will say like this:
1. There are two car who travel 160 miles apart and meet in 2 hours. So first, I would think of each car is 40 mph, because two cars travel 80 in one hour, and two hours will be 160.
2. Then, the first car will travel with the speed is 34 mph and the other one will be 46 mph, because one car travels 6 mph faster than one car.
Answer: 4
Step-by-step explanation: