Your answer is 406.8. You just multiply 10 by itself, the answer is 100, then you multiply 100 by 4.068.
Answer:
144
Step-by-step explanation:
320 ÷ 20 = 16
adults : children
11 : 9
9×16 = 144

Dividing by a fraction is the same as multiplying by its reciprocal. (flipped version)

6 and 9 are both divisible by 3, so we can simplify 6/9 = 2/3.

We can multiply across right now, but we might as well cross cancel.
Look at the numbers diagonal from one another...-3 and 3 are both divisible by 3, so we can change them to -1 and 1...2 and 2 are both divisible by 2, so we can change them to 1 and 1...

Any fraction over 1 can just be expressed as a whole number.

Our final answer...

If you were to multiply across, (maybe you don't like cross cancelling, idk?) you'd get the same answer, of course.
Given the population mean is
and population standard deviation is
.
Now sample mean is
and standard deviation of the sample mean is
.
Use Z-score for finding the probabilities. Use a standard normal distribution table.
a)The probability

b)The probability

c)The probability
