Arithmetic Ability
 Probability

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Q.

A letter is takenout at random from 'ASSISTANT' and another is taken out from 'STATISTICS'. The probability that they are the same letter is :

View Answer

Correct choice: B

Explanation:

ASSISTANT→AAINSSSTT STATISTICS→ACIISSSTTT Here N and C are not common and same letters can be A, I, S, T. Therefore Probability of choosing A = 2C1/9C1×1C1/10C1 = 1/45 Probability of choosing I = 1/9C1×2C1/10C1 = 1/45 Probability of choosing S = 3C1/9C1×3C1/10C1 = 1/10 Probability of choosing T = 2C1/9C1×3C1/10C1 = 1/15 Hence, Required probability = 1/45+1/45+1/10+1/15= 19/90
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