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You randomly pick two numbers from 1 to 9 (including 1 and 9). If you could pick the same number twice and the first of the two numbers is odd and less than 5, then the probability that the sum of the two numbers is less than 5 is .

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solution-

If we have to choose an odd number less than 5, then that number must be either 1or 3.

therefore, the probability of choosing these two numbers out of 9 numbers (that is from 1 to 9)=(2/9).

There is a 50% (that is 0.5) chance that the first number is 1 .

If it is 1, and their sum is less than 5, then the second number is 1, 2, or 3 .

The probability that it is chosen from 9 numbers=(3/9)

There is also a 50% (that is 0.5) chance that the first number is 3 .

If it is 3, and their sum is less than 5, then the second number will be 1 .

Therefore, the probability that it is chosen from 9 numbers=(1/9)

Therefore, the probability that the sum of the two numbers is less than 5 is-

=(2/9)×[ (0.5 x 3/9) + (0.5 x 1/9) ] = (2/9)×[1.5/9+0.5/9]

=(2/9)×(2/9)

=4/81 =0.0494 =4.94% (approx.)

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