Mathematics - Permutation & Combination Question with Solution | TestHub

MathematicsPermutation & CombinationDivision of Identical itemsMedium2 minQB

MathematicsMediumsingle choice

The total number of positive integral solutions of the inequality $15 < x_{1} + x_{2} + x_{3} \leq 20$ is

Answer:

Solution:

$x_{1} + x_{2} + x_{3} = 16 + r, r = 0, 1, 2, 3, 4$

Number of positive integral solutions $=^{15 + r} C_{2}$

Required number of solutions $= \sum_{r = 0}^{4} (15 + r)_{C_{2}}$

Stream:JEESubject:MathematicsTopic:Permutation & CombinationSubtopic:Division of Identical items

⏱ 2mℹ️ Source: QB

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