If 20 men working 7 hours a day can do a piece of work in 10 days, in

1.	If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working 8 hours a day do the same piece of work ?(a) \(15\frac{5}{21}\) days(b) \(11\frac{2}{3}\) days(c) \(6\frac{9}{16}\) days(d) \(4\frac{1}{5}\) days
Answer» (b) \(11\frac{2}{3}\) days 20 men working 7 hours a day can complete the work in 10 days. 20 men working 1 hour a day can complete the work in (10×7) days (Less hours \(\Rightarrow\) More days) 1 man working 1 hour a day can complete the work in (10×7×20) days (Less men \(\Rightarrow\) More days) 1 man working 8 hours a day can complete the work in \(\frac{(10\times7\times20)}{8}\) days (More hours \(\Rightarrow\) Less days) 15 men working 8 hours a day can complete the work in \(\big(\frac{10\times7\times20}{8\times15}\big)\) days (More men \(\Rightarrow\) Less days) = \(\frac{35}{3}\) days = \(11\frac{2}{3}\) days

If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working 8 hours a day do the same piece of work ?(a) \(15\frac{5}{21}\) days(b) \(11\frac{2}{3}\) days(c) \(6\frac{9}{16}\) days(d) \(4\frac{1}{5}\) days

Answer»

(b) \(11\frac{2}{3}\) days

20 men working 7 hours a day can complete the work in 10 days.

20 men working 1 hour a day can complete the work in (10×7) days

(Less hours \(\Rightarrow\) More days)

1 man working 1 hour a day can complete the work in (10×7×20) days (Less men \(\Rightarrow\) More days)

1 man working 8 hours a day can complete the work in \(\frac{(10\times7\times20)}{8}\) days

(More hours \(\Rightarrow\) Less days)

15 men working 8 hours a day can complete the work in \(\big(\frac{10\times7\times20}{8\times15}\big)\) days

(More men \(\Rightarrow\) Less days)

= \(\frac{35}{3}\) days = \(11\frac{2}{3}\) days