COMEDK · Maths · 4. Permutation Combination
In a 12 storey house, 10 people enter a lift cabin. It is known that they will leave the lift in pre-decided groups of 2, 3 & 5 people at different storeys. The number of ways they can do so if the lift does not stop up to the second storey is
- A 78
- B 720
- C 132
- D 120
Answer & Solution
Correct Answer
(B) 720
Step-by-step Solution
Detailed explanation
The total number of storeys available is 12. Since the lift does not stop at the first and second storeys, the available storeys for the groups to exit are from the 3rd to the 12th storey. This gives \(12 - 2 = 10\) available storeys. There are 3 groups of people consisting of…
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