Question

2 sets a and b are having 99 elements in common then no of elements common to each of the sets a×b and b×a

Answer 1

a and b having 99 elements in common .
Then number of elements common to each of the sets a × b and b × a = 99 × 99
= (99)² = 9801 .

Actually, you can see choose 99 elements which are common to both a and b in 99 ways separately in both the cases .
And when you will multiple these you will get the same number of elements e.g., a × b = (99)² and b × a = (99)²

So, tbe answer should be 99² = 9801

Answer 2

Hello Dear.

Here is the answer---


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Sets a and b have 99 elements common to each other.

Thus, the Number of elements common to each other (a × b) will be 99 × 99
 = 9801

Number of Elements common to each other(b × a) will be 99 × 99
 = 9801.

From this, we can say that---
For both the sets, the number of elements common to each other is 9801.

Thus, the number of elements common to both the sets (a × b) and (b × a) is 9801.


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Hope it helps.

Have a Nice day.