the amount of sleep that elementary school children get per night follows a normal distribution with a mean of 9.5 hours and a standard deviation of 0.55 hours. is it unusual for an elementary student to get at least 12 hours of sleep?

Yes, that is unusual as the problem is given.

Step-by-step explanation:

If the mean is 9.5 and the standard deviation is 0.55, then anything within the normal curve of 10.05 on the high end and 8.45 on the low end is normal. 12 is more than several standard deviations or an outlier if this makes sense.

So, it is unusual as the problem is stated, but if it's a weekend, 12 hours is normal. LOL

Good luck!  

arrange the equations with like terms in columns.

analyze the coefficients of x or y.

add the equations and solve for the remaining variable.

substitute the value into either equation and solve.

check the solution.

step-by-step explanation:

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.