Let's use J for James's age and A for Austin's age. The equations are:
J = A - 4
3J + A² = 28
Just plug (A - 4) in the place of J in the second equation. This gives you:
3(A - 4) + A² = 28
-->
A² + 3A - 12 = 28
-->
A² + 3A - 40 = 0
-->
(A - 5)(A + 8) = 0
-->
A = 5 or -8
-8 is nonsense, so Austin is 5 years old. Therefore, James is 1 year old.
Answer:
the rate is: 6 cups of flour per cup of water
Step-by-step explanation:
Recall that rate involve quotient of the two quantities in question:
Then cups of flour per cups of water is the quotient: 2 cups of flour divided by 1/3 cup of water:

this means 6 cups of flour per cup of water
Answer:
0.8894 is the probability that the test result comes back negative if the disease is present
.
Step-by-step explanation:
We are given the following in the question:
P(Disco Fever) = P( Disease) =

Thus, we can write:
P(No Disease) =

P(Test Positive given the presence of the disease) = 0.99

P( false-positive) = 4%

We have to evaluate the probability that the test result comes back negative if the disease is present, that is
P(test result comes back negative if the disease is present)
By Bayes's theorem, we can write:

0.8894 is the probability that the test result comes back negative if the disease is present
.