Answer:
a) For this case we can use the definition of weighted average given by:

And if we replace the values given we have:

b) 
c) 
Step-by-step explanation:
Assuming the following question: "One sample has a mean of M=8 and a second sample has a mean of M=16 . The two samples are combined into a single set of scores.
a) What is the mean for the combined set if both of the original samples have n=4 scores
"
For this case we can use the definition of weighted average given by:

And if we replace the values given we have:

b) what is the mean for the combined set if the first sample has n=3 and the second sample has n=5
Using the definition we have:

c) what is the mean for the combined set if the first sample has n=5 and the second sample has n=3
Using the definition we have:

Answer: -54
Step-by-step explanation:
Answer:
he should divide to find how many students
Step-by-step explanation:
30 ÷5=6
Answer:
D
Step-by-step explanation:
It just is
1) Never heard of someone referring to the Law of Levers before, must be showing my age. A system as you describe is at equilibrium when the net torque is equal to zero. Since torque is Fr=mgr so for this system we have a sum of:
27g*10+30g*x=0 The sum must be zero to be at equilibrium, dividing both sides by g you have:
270+30x=0
270=-30x
x=-9
The negative just indicates that the magnitude of 9 is on the opposite side of the fulcrum, so x=9ft in magnitude.
2) Inverse variation is of the form y=k/x, in this case we are given a point so we can solve for the constant, k, of variation...
y=k/x, and we are given y=-12 when x=5 so
-12=k/5
k=-60 so the equation is:
y=-60/x which can be expressed as
xy=-60