Evan washes two types of vehicles. It takes him 30 minutes to wash a car and 40 minutes to wash a truck. He charges $12 to wash
a car and $15 to wash a truck. In 270 minutes, Evan made $105 washing cars and trucks. How many trucks did Evan wash?
2 answers:
Answer:
Step-by-step explanation:
Let
x-----> the number of cars
y----> the number of trucks
we know that
-----> equation A
-----> equation B
Using a graphing tool
Remember that the solution of the system of equations is equal to the intersection point both graphs
In this problem the intersection point is
see the attached figure
therefore
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Answer:
μ= 65 inches; σ= 0.625 inch
Step-by-step explanation:
The Central Limit Theorem estabilishes that, for a normally distributed(bell-shaped) random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this problem, we have that:
By the central limit theorem, the sample of 16 will have:
So the correct answer is:
μ= 65 inches; σ= 0.625 inch