Question
Fri April 06, 2012 By:

Let A = {2, 4, 6, 8, 10} and B = {(a, b) : a divides b; a , b A}. Write the elements of B.

Expert Reply
Sun April 08, 2012
In the question, we have to write the elements of the set B. By definition of set B, the elements of this set will be the ordered pairs (a, b) such that a divides b, that is, b is divisible by a. Note that here a and b are the elements of A. This means that a and b can take values 2, 4, 6, 8, and 10 only.
 
So, now to find the elements of set B,find the ordered pairs such that b is divisible by a. It can be seen that 2, 4, 6, 8, 10 are divisible by 2 and also 4 and 8 are divisible by 4.
 
Hence, B = {(2, 2), (2, 4), (2, 6), (2, 8), (2, 10), (4, 4), (4, 8)}
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