A, B and C can do a piece of work in 10 days, 12 days and 15 days resp

1.	A, B and C can do a piece of work in 10 days, 12 days and 15 days respectively. How long will they take to finish it if they work together?
Answer» Number of days A required do a piece of work : 10 Number of days B required do a piece of work : 12 Number of days C required do a piece of work : 15 Work done by A in one day: \(\frac{1}{10}\) Work done by C in one day: \(\frac{1}{12}\) Work done by C in one day: \(\frac{1}{15}\) Work done by A, B and C together in one day: \(\frac{1}{10}+\frac{1}{12}+\frac{1}{15}=\frac{15}{60}=\frac{1}{4}\) ∴ They can do the work together in 4 days .

A, B and C can do a piece of work in 10 days, 12 days and 15 days respectively. How long will they take to finish it if they work together?

Answer»

Number of days A required do a piece of work : 10

Number of days B required do a piece of work : 12

Number of days C required do a piece of work : 15

Work done by A in one day: \(\frac{1}{10}\)

Work done by C in one day: \(\frac{1}{12}\)

Work done by C in one day: \(\frac{1}{15}\)

Work done by A, B and C together in one day: \(\frac{1}{10}+\frac{1}{12}+\frac{1}{15}=\frac{15}{60}=\frac{1}{4}\)

∴ They can do the work together in 4 days .