Answer:
C: 
Step-by-step explanation:

Since a =
:

Since n = 4 :

Answer:
Just put the numbers in order then the interquartile range would be the largest number from the high quartile and the lowest number from the lower quartile.
45% of what number is 27
0.45x = 27
x = 27 / 0.45
x = 60 <== 45% of 60 = 27
Answer:
See explanation
Step-by-step explanation:
1 step:
n=1, then

So, for j=1 this statement is true
2 step:
Assume that for n=k the following statement is true

3 step:
Check for n=k+1 whether the statement

is true.
Start with the left side:

According to the 2nd step,

Substitute it into the 

So, you have proved the initial statement