Answer:
a) 279 b)254
Step-by-step explanation:
Mean = 269 days
standard deviation = 8 days
let n be the pregnancy lenght.
using normal distribution formula
z = (n – mean)/ standard deviation
n = z * standard deviation + mean
Now, z values for the top 12% has to be found using a z table.
The top 12% means 88% of area under the curve. In this case z = 1,176
n = 1,176 * 8 + 269
n = 278.4 = 279
The bottom 3% means 97% of area under the curve. In this case z = -1,882
n = -1,882 * 8 + 269
n = 253.94 = 254
So since we know what x is, we can substitute it into the original equation for x like so to solve for y...
(2y - 8) + 5y - 10 = 0
2y - 8 + 5y = 10
2y + 5y = 18
7y = 18
y = 18/7 (or about 2.57)
So now we know what x is, we can sub it into the below equation to solve for x...
x = 2(18/7) - 8
x = 36/14 - 8 (or about -5.43)
Answer:
Step-by-step explanation:
I can not see your answers to choose but with this equation for 2 variables, you can replace the values of x and y and see if that is right or not.
For example, to know (-2,5) is a solution, you replace x= -2 and y= 5
into this equation: -3x -y = 6
and you have: -3*(-2) -5 =6
or 6-5 =6, and you find that is impossible, so (-2.5) is not a solution.
Hope you understand it
