Rectangular Magic grid

This is similar to a magic square.I am presenting a rectangular grid with 2 rows and 3 columns.
Each row contains 3 numbers and the sum of the numbers in each row is the same
Each column contains 2 numbers and the sum of the numbers in each column is the same
No number gets repeated anywhere.
Following are 2 examples-
1)First row-..........1      8      9
   Second row......11     4      3..   Each row totals 18 and each column totals 12
2)First row......................................1      10     7
    Second row................................11      2     5.....similar to 1) above

I am also giving 2 examples of rectangular grids with 4 numbers in each row and 3 numbers in each column
1)........1      4     15    12
           5      11    6      10
          18      9     3       2....     each row total 32 each column total 24
2)                                       1       4       11     16
                                          9.      7        10     6
                                         14      13       3      2     similar to previous example
You can make such rectangular grids easily with large numbers but it is difficult if you use small numbers
You can also have more numbers each row and more numbers each column

Puzzle about 3 variables a,b,c

Three variables are governed by the relation a^2+b^2=c^2
Can you find which of the following is true?
1)(a+b)=c
2)(a+b)>c
3)(a+b)<c
You have to explain your reasoning.

Selection /Deletion of numbers

Suppose I first make a list of all the consecutive numbers from unity.
Suppose next I delete all the numbers which contain the digit 3 as well as those which are multiples of 3.
From the list of the remaining numbers,can you tell me what will be  the 40th number or the 50th number?
Suppose I next also delete from this new list all numbers containing the digit 4 as well as multiples of 4.
What will be the 30th number now? 

Group of 8 numbers

The average of the 8 numbers forming a group is 20.The average of the first 2 numbers is 15.5 and the average of the next 3 is 64/3.If the 6th number is less than the seventh and eighth by 4 and 7 respectively,find the 8th number

Birthdays for twins

Here is a puzzle for you-
A mother gives birth to two boys as twins.
The younger twin should normaly celebrate his birthday later than his older twin brother.
In a prticular case however the younger twin celebrates it earlier.
How is it possible?

Filling up of a sequence-2

This is with reference to my earlier blog-same title.
In spite of my hint that the solution is in the question itself nobody has responded.
The question was-'Anybody willing to work out the next two numbers in the sequence below?'
You have to look at the number of alphabets in each word in the sentence above forming the question
The numbers of alphabets in successive words are 7,7,2,4,3,3,4,3,7,2,3.The last two words viz 'sequence' and 'below' contain 8 and 5 alphabets respectively and thus these two numbers 8 and 5 are the numbers filling up the sequence .

One set of faulty coins-2

This is a rejoinder to my earlier blog of same title.
A correct reply has already been given by Shekar which may be seen under the comment portion.
The reply holds good if the weighing machine is capable to weigh correctly  upto the weight of around 55 coins.Suppose it is capable to weigh correctly upto the weight of say around 45,46 etc of coins.In that case you must take no coins from one set,which you can mark.If all coins weigh correctly the total weight should be that of 45 coins,(45 being the sum of digits 1 to 9) and so the actual weight differring from weight of 45 coins will show you which set has the faulty coins.