Multiple choice

A and B can finish a work in 24 days and 36 days respectively. They started the work together but often few days A left and B finished the remaining work in 16 days. Find after how many days did A leave. A और B किसी कार्य को क्रमशः 24 दिन तथा 36 दिन में समाप्त करते हैं। दोनों ने कार्यों को एक साथ प्रारम्भ किया लेकिन कुछ दिनों पश्चात् A कार्य छोड़कर चला गया तथा B ने शेष कार्य 16 दिनों में समाप्त किया। बताइये कितने दिनों पश्चात् A ने कार्य करना छोड़ दिया?

  1. 5 days 5 दिन

  2. 4 days 4 दिन

  3. 7 days 7 दिन

  4. 6 days 6 दिन

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Let A work for d days. Work done by both in d days = d(1/24 + 1/36) = d(5/72). Work done by B alone for 16 days = 16/36 = 4/9. Total work: d(5/72) + 4/9 = 1. Solving: 5d/72 + 32/72 = 72/72, so 5d = 40, d = 8. But wait, rechecking: A's rate = 1/24, B's rate = 1/36. Combined work for d days: d(1/24 + 1/36) = d(5/72). B alone for 16 days: 16/36 = 4/9. 5d/72 + 4/9 = 1 gives 5d/72 = 5/9, so d = 8. The answer 8 is not in options A-D.

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