Mathematics - Probability Question with Solution | TestHub

MathematicsProbabilityGeneral (Event SS, Definitions, Odd against/Favour)Medium2 minQB

MathematicsMediuminteger

A seven digit number made up of all distinct digits $8, 7, 6, ∠, 2, x, y$ is divisible by 3 . The possible number of ordered pairs $(x, y)$ is

Answer:

Solution:

We know that a number is divisible by 3 . If sum of its digits is divisible by 3 . Hence we must have $8 + 7 + 6 + 4 + 2 + (x + y) = 3 k$

$27 + x + y = 3 k$

$\Rightarrow x + y$ is multiple of 3

Hence required $(x, y)$ order pairs

$= (0, 3), (0, 9), (1, 5), (3, 0), (3, 9), (5, 1), (9, 0), (9, 3)$

Stream:JEESubject:MathematicsTopic:ProbabilitySubtopic:General (Event SS, Definitions, Odd against/Favour)

⏱ 2mℹ️ Source: QB

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