Walking 5/7 of his usual speed, a person reaches his office 10 minutes later than the usual time. His usual time in minutes is?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 25
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Concept |
Understanding |
Application |
Fair calculation |
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Time = Distance/Speed |
Let the usual speed of the person be S Distance = D
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Speed of the person after decreasing = 5S/7 D/(5S/7) – D/S = 10 7D/5S – D/S = 10 ⇒2D/5S = 10 ∴D/S = 10 ×5/2 = 25 min |
10 ×5/2 = 25 |