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Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationFundamental PrincipleMedium2 minQB

MathematicsMediumsingle choice

Let $a = a_{1} a_{2} a_{3}$ and $b = b_{1} b_{2} b_{3}$ be two three digit numbers. How many pairs of 'a' and 'b' can be formed so that ' a ' can be subtracted from ' b ' without borrowing?

Options:

Answer:

Solution:

Number of cases $= (1 + 2 + 3 + \dots\dots + 9) (1 + 2 + 3 + \dots .. + 10)^{2} = 45 (55)^{2}$

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

⏱ 2mℹ️ Source: QB

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