Question 1200342
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A box contains 10 chits of which 3 chits are eligible for a prize. 
A boy named Kathan randomly selects two chits from this box. 
Find the probability that Kathan gets the prize.
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<pre>
The box containins two categories of chits: 

        (a) 3 Good for a prize,  
    and 
        (b) 7 Bad for a prize.


The total number of pairs to take at a time from 10 shits is

    {{{C[10]^2}}} = {{{(10*9)/2}}} = 45.


The total number of pairs BAD for the prize is

    {{{C[7]^2}}} = {{{(7*6)/2}}} = 21.


The rest of the pairs, 45 - 21 = 24, will win a prize.


Therefore, the probability to win a prize is  P = {{{24/45}}} = {{{8/15}}}.    <U>ANSWER</U>
</pre>

Solved, with full explanation. 


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