Explain why triangle ABC is isoceles.
1 answer:
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Answer:
D. (10, 15)
Step-by-step explanation:
Hi there!
We are given the following system:
+y=20
x+4y=70
And we want to solve it (find the values of x and y).
Let's use substitution for this problem, where we will isolate one variable on one side, while the other side contains an expression with the other variable. Then, we use the expression to solve for the variable that the expression contains, then use the value of that variable to solve for the aforementioned isolated variable.
Subtract from both sides in the first equation
y=20-
Now substitute 20- as y in x+4y=70
x+4(20-)=70
Do the distributive property
x+80-2x=70
Combine like terms on the left
-x+80=70
Subtract 80 from both sides
-x=-10
Multiply both sides by -1
x=10
We found the value of x. Now let's use that value to find what y is
Since we know that y=20- and x=10, we can substitute 10 as the value of x to solve for y
In that case,
y=20-(10)
Multiply
y=20-5
Subtract
y=15
The answer is x=10, y=15, or as a point, <u>(10, 15), aka D</u>
Hope this helps!
Complete question :
A company is manufacturing highway emergency ares. Such ares are sup- posed to burn for an average of 20 minutes. Every hour a sample of ares is collected, and their average burn time is determined. If the manufacturing process is working cor- rectly, there is a 68% chance that the average burn time of the sample will be between 14 minutes and 26 minutes. The quality engineer in charge of the process believes that if 4 of 5 samples fall outside these bounds then this is a signal that the process might not be performing as expected. Each morning the sampling begins anew. Let X denote the number of samples drawn in order to obtain the fourth sample whose average value is outside of the above bounds. Find the probability that for a given morning X = 5, hence there seems to be a problem right away.
Answer:
0.0285
Step-by-step explanation:
We are to find the probability for a given morning that X = 5
From the question, we could see that there is a 68% chance that the average burn time of the sample will be between 14 minutes and 26 minutes and the success of the process is obtained after the fourth or fifth sample.
Thus, r = 4; q = 0.68
The probability average burn time falls outside p will be:
p = 1 - 0.68 = 0.32
The random variable X follows negative binomial distribution.
Therefore,
Where, x = 5
r = 4
p = 0.32
Substituting figures in the equation, we have:
= 0.0285
The probability that for a given morning X = 5 is 0.0285