Mathtips

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Solution for yesterday’s problem

If peter takes ‘t’ hours John takes t-3 hours

Also, as John is twice efficient he takes half the time to complete the same work. Therefore, t = 2(t-3) => t = 6 hours.

So, John takes 3 hours and Peter takes 6 hours.

Together they take 6*3/(6+3) = 2 hours; ab/(a+b)

Today’s problem

A can do a work in 18 days, B in 9 days, and C in 6 days. A and B start the working together and after 2 days C joins them. What is the total number of days taken to finish the work?

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