Answer: (a) 0.344578
(b) 0.211855
Step-by-step explanation: Let X represent Jill's score and Let Y represent Jack's score.
Jill's scores are approximately normally distributed with mean 170 and standard deviation 20 implies :
X ≈(170 ,
)
Also , since Jack's scores are approximately normally distributed with mean 160 and standard deviation, it implies
Y ≈ ( 160 ,
).
It is given that their scores are independent which means that the outcome one one will not affect the outcome of the other, we the have:
Y - X ≈ N(-10 ,
+
)
Y - X ≈ N(-10 ,625 )
Also , Y + X ≈ N ( 330 , 625 )
(a) We need to find the approximate probability that Jack's score is higher , that is
P ( Y > X)
=P(Y - X >0)
= P (
> ![\frac{10}{\sqrt{625} }](https://tex.z-dn.net/?f=%5Cfrac%7B10%7D%7B%5Csqrt%7B625%7D%20%7D)
= 1 - Ф(
)
= 1 - Ф(
)
= 1 - Ф ( 0.4)
= 1 - 0.655422
= 0.344578
P ( Y > X) ≈ 0.345
(b) We need to calculate the approximate probability that their total score is above 350 , that is
P ( X + Y > 350)
= P (
>
)
= 1 - Ф(
)
= 1 - Ф ( 0.8)
= 1 - 0.788145
= 0.211855
P ( X + Y > 350)≈ 0.212
Step-by-step explanation:
30 im sure that ia the corect answer
Answer:
261
Step-by-step explanation:
Answer:
b = 10
b = 17
Step-by-step explanation:
Hello!
Usually, when you want two different integer solutions, you probably want the quadratic to be factorable.
So what we want to know is that b should be the sum of the factors in 16.
Factors of 16: 1, 2, 4, 8, 16
Factor pairs:
Factor Sums:
These are our possible b-values.
Check:
Let's try 17 first:
- x² - 17x + 16 = 0
- (x - 16)(x - 1) = 0
- x = 16, x = 1
Now 10:
- x² - 10x + 16 = 0
- (x - 8)(x - 2) = 0
- x = 8, x = 2
And finally, 8:
- x² - 8x + 16 = 0
- (x - 4)(x - 4) = 0
- x = 4, x = 4
Since x = 4 is a repetitive integer, we cannot use 8 as a value for b.
The answers are b = 10, and b = 17.
Answer:
D.
Step-by-step explanation:
You cannot plan your thoughts if you are just thinking out loud.