Answer:
600
Step-by-step explanation:
x+2x=1800
3x=1800
x=600
Answer:
The standard deviation of the sample mean is
Step-by-step explanation:
From the question we are told that
The mean is 
The standard deviation is 
The sample size is 
Generally the standard deviation of the sample mean is mathematically represented as

substituting values


I think
113.04 will be the answer.
Using Pythagoras:
12^2+5^2= 144+25=169
√169= 13
Answer: 21
Step-by-step explanation: hope this helps :)