Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationFundamental PrincipleEasy2 minQB

MathematicsEasysingle choice

The number of different 7 digit numbers that can be written using only the three digits 1, 2 and 3 with the condition that the digit 2 occurs twice in each number is

Options:

Answer:

Solution:

Other than 2, remaining five place are to be filled by 1 \& 3

∴ No. of ways for five places $= 2^{5}$

For 2, selecting 2 places out of $7 =^{7} C_{2}$

∴ Required no. of ways $=^{7} C_{2} 2^{5}$

Stream:JEESubject:MathematicsTopic:Permutation & CombinationSubtopic:Fundamental Principle

⏱ 2mℹ️ Source: QB

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