Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationFundamental PrincipleMedium2 minQB

MathematicsMediumsingle choice

How many times is the digit 5 written when listing all numbers from 1 to 1,00,000 ?

Answer:

Solution:

$= 5 \times 9^{4} \times 1 +^{5} C_{2} \times 9^{3} \times 2 +^{5} C_{3} \times 9^{2} \times 3 +^{5} C_{4} \times 9 \times 4 +^{5} C_{5} \times 5$

$= 5 \times 1 0^{4}$

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

⏱ 2mℹ️ Source: QB

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