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    Question

    A cistern is normally filled in 8 hours but

    takes 2 hours longer to fill because of a leak in it's bottom. If the cistern is full, the leak will empty it in?
    A 16 hrs Correct Answer Incorrect Answer
    B 40 hrs Correct Answer Incorrect Answer
    C 35 hrs Correct Answer Incorrect Answer
    D 25 hrs Correct Answer Incorrect Answer

    Solution

    Filled in 1 hour = [if gte vml 1]> [if !vml]-->`1/8` [endif]--> part Filled in 1hour with leakage = `1/10` part Leakage in 1 hours = `1/8-1/10=2/(8xx10)=1/40` 40 hours. Alternate Solution: Let B is the leak, So A A+B 8 10 hrs LCM = 40 L Eff 5 : 4 So B's 1 hr work = 4-5= -1 units, Hence B will emplty 1 L in 1 hr So it will empty the whole tank in = 40/1= 40 hr

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