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प्रश्न
A school has three gates and four staircases from the first floor to the second floor. How many ways does a student have to go from outside the school to his classroom on the second floor?
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उत्तर
3 gates to enter the school.
4 staircases to go from the first floor to the second floor.
∴ the number of ways of going to the classroom is
`=(("The number of ways"),("to enter the school")) xx (("The number of ways to"),("go to the second floor"))`
= 3 × 4
= 12 ways
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