ANSWER

EXPLANATION
We want to evaluate

Use indices to rewrite the expression as:

We know that

So we rewrite the expression to obtain;

This gives us;

This simplifies to


This means for every 5 students there will be 1 teacher so 550/5=110
So answer is 110 teachers
Hi there!
To split 90 kilos in the ratio of 2 : 3 : 7 we must first realise that we have a total of 2 + 3 + 7 = 12 parts, in which we must split the total 90 kilos.
12 parts equal 90 kilo, and therefore
1 part equals 90 / 12 = 7.5 kilos.
1 part equals 90 / 12 = 7.5 kilos, and therefore
2 parts equal 7.5 × 2 = 15 kilos.
1 part equals 90 / 12 = 7.5 kilos, and therefore
3 parts equal 7.5 × 3 = 22.5 kilos.
1 part equals 90 / 12 = 7.5 kilos, and therefore
7 parts equal 7.5 × 7 = 52.5 kilos.
Hence, 90 kilos in the ratio of 2 : 3 : 7
gives 15 kg, 22.5 kg and 52.5 kg.
~ Hope this helps you!
Answer:
> a<-rnorm(20,50,6)
> a
[1] 51.72213 53.09989 59.89221 32.44023 47.59386 33.59892 47.26718 55.61510 47.95505 48.19296 54.46905
[12] 45.78072 57.30045 57.91624 50.83297 52.61790 62.07713 53.75661 49.34651 53.01501
Then we can find the mean and the standard deviation with the following formulas:
> mean(a)
[1] 50.72451
> sqrt(var(a))
[1] 7.470221
Step-by-step explanation:
For this case first we need to create the sample of size 20 for the following distribution:

And we can use the following code: rnorm(20,50,6) and we got this output:
> a<-rnorm(20,50,6)
> a
[1] 51.72213 53.09989 59.89221 32.44023 47.59386 33.59892 47.26718 55.61510 47.95505 48.19296 54.46905
[12] 45.78072 57.30045 57.91624 50.83297 52.61790 62.07713 53.75661 49.34651 53.01501
Then we can find the mean and the standard deviation with the following formulas:
> mean(a)
[1] 50.72451
> sqrt(var(a))
[1] 7.470221
He walks 7,300 miles in 1 year