Answer:
tons of high steel and
tons of low steel
Step-by-step explanation:
Let x be the number of tons of high grade steel and y be the number of tons ow low grade steel needed.
In x tons of high grade steel there are
tons of iron
tons of magnese
In y tons of low grade steel there are
tons of iron
tons of magnese
NASA orders 500 tons of steel, so

and specifies that it must be in the proportion 80% iron and 20% magnese, so

From the first equation,

Substitute it into the second equation:

<h2>
Answer with explanation:</h2><h2 />
The confidence interval for population mean is given by :-

Given : Sample size : n= 5, since n<30 , so the test we use here is t-test.
Sample mean : 
Standard deviation: 
Significance level : 
By using the standard normal distribution table , the critical value corresponds to the given significance level will be :-

Now, the 99% confidence interval for the mean waste recycled per person per day for the population of Texas will be :-

Hence, the 99% confidence interval for the mean waste recycled per person per day for the population of Texas = (0.068, 3.732)
Answer:
B
Step-by-step explanation: