Question:
There are two main entrances to a building with five floors. Each entrance leads to three lifts and each lift can stop at all the five floors. A person enters the building and reaches a floor. The number of possible ways that the person can reach the floor, is
There are two main entrances to a building with five floors. Each entrance leads to three lifts and each lift can stop at all the five floors. A person enters the building and reaches a floor. The number of possible ways that the person can reach the floor, is
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When choices are independent, multiply them to get total number of outcomes.
Updated On: Apr 24, 2026
- $15$
- $25$
- $10$
- $30$
- $50$
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The Correct Option is D
Solution and Explanation
Concept:
• Use Fundamental Principle of Counting
• Total ways = product of independent choices
Step 1: Identify choices
• Number of entrances = 2
• Number of lifts per entrance = 3
• Number of floors = 5
Step 2: Apply multiplication principle
\[ \text{Total ways} = 2 \times 3 \times 5 = 30 \] Final Conclusion:
\[ = 30 \]
• Use Fundamental Principle of Counting
• Total ways = product of independent choices
Step 1: Identify choices
• Number of entrances = 2
• Number of lifts per entrance = 3
• Number of floors = 5
Step 2: Apply multiplication principle
\[ \text{Total ways} = 2 \times 3 \times 5 = 30 \] Final Conclusion:
\[ = 30 \]
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