Alright, lets get started.
Missing number fom the series : 9, ..... , 6561, 43046721
43046721 is square of its previous number 6561, means
It means the missing number will be square of its previous number
Means 
, so missing number is 81. : Answer
Next : one number is 2 more than 3 times another. their sum is 22. find the numbers.
Suppose one number is x and second number is y
As per given equation, 
......equation (1)
Their sum is 22 means, 
.......equation (2)
Putting the value of x from equation1 into equation 2
Subtracting 2 in both sides
Means numbers are 17 and 5. : Answer
Next : the missing number in the series 1, 4, 27,____, 3125 is
1 could be written as 1
4 could be written as 
27 could be written as 
So , next number would be 
Next one is 
So, the missing number is 256 : Answer
Next : the next number in the series 3, 4, 6, 7, 9, 10 is
After 3,4 (5) is mising, 6, 7 (8) is missing, 9, 10 (11) will be missing
So, next number will be 12. : Answer
Next : a farmer is planting a straight row of crops with 3 feet between each plant. if 23 are planted, what is the distance between the first and last plant?
Between 2 plants, the distance is = 
Between 3 plants, the distance is = 
So, between 23 plants, the distance is = 
hene the distance between first and last plant woule be 66 feet. : Answer
