Question Number 7467 by Obenfo last updated on 30/Aug/16
$$\mathrm{5}\:\mathrm{men}\:\mathrm{or}\:\mathrm{10}\:\mathrm{women}\:\mathrm{can}\:\mathrm{complete}\:\mathrm{a}\:\mathrm{work} \\ $$$$\mathrm{in}\:\mathrm{20}\:\mathrm{days}.\:\mathrm{In}\:\mathrm{how}\:\mathrm{many}\:\mathrm{days}\:\mathrm{can}\:\mathrm{3}\:\mathrm{men} \\ $$$$\mathrm{and}\:\mathrm{4}\:\mathrm{women}\:\:\mathrm{complete}\:\mathrm{it}? \\ $$
Commented by FilupSmith last updated on 31/Aug/16
$$\mathrm{attempt}\:−\:\mathrm{unsure}\:\mathrm{if}\:\mathrm{correct}. \\ $$$$ \\ $$$$\mathrm{5}{m}=\mathrm{20}\:\Rightarrow\:{m}=\mathrm{4} \\ $$$$\mathrm{10}{w}=\mathrm{20}\:\Rightarrow\:{w}=\mathrm{2} \\ $$$$ \\ $$$${x}=\mathrm{3}{m}+\mathrm{4}{w}=\mathrm{3}\left(\mathrm{4}\right)+\mathrm{4}\left(\mathrm{2}\right) \\ $$$${x}=\mathrm{12}+\mathrm{8} \\ $$$${x}=\mathrm{20} \\ $$
Answered by Rasheed Soomro last updated on 31/Aug/16
$$\mathrm{5}\:{men}=\mathrm{10}\:{woman} \\ $$$$\mathrm{1}\:{man}=\mathrm{2}\:{women} \\ $$$$\mathrm{3}\:{men}=\mathrm{6}\:{women} \\ $$$$\mathrm{3}\:{men}+\mathrm{4}\:{women}=\mathrm{6}\:{women}+\mathrm{4}\:{women}=\mathrm{10}\:{women} \\ $$$$\mathrm{10}\:{women}\:{can}\:{complete}\:{a}\:{work}\:{in}\:\mathrm{20}\:{days}\:\left[{Given}\right] \\ $$$$\therefore\mathrm{3}\:{men}+\mathrm{4}\:{women}\:{can}\:{complete}\:{a}\:{work}\:{in}\:\mathrm{20}\:{days} \\ $$$$ \\ $$
Commented by sandy_suhendra last updated on 31/Aug/16
$${Great}\:{approach}! \\ $$
Answered by sandy_suhendra last updated on 31/Aug/16
$${another}\:{answer} \\ $$$$\mathrm{5}\:{men}\:=\:\mathrm{20}\:{days}\:\Rightarrow\:\mathrm{1}\:{man}\:=\:\mathrm{100}\:{days} \\ $$$$\mathrm{1}\:{man}\:{in}\:\mathrm{1}\:{day}\:=\:\frac{\mathrm{1}}{\mathrm{100}}\:{part}\:{of}\:{work} \\ $$$$\mathrm{3}\:{men}\:{in}\:\mathrm{1}\:{day}\:=\:\frac{\mathrm{3}}{\mathrm{100}}\:{part}\:{of}\:{work} \\ $$$$\mathrm{10}\:{women}\:=\:\mathrm{20}\:{days}\:\Rightarrow\:\mathrm{1}\:{woman}\:=\:\mathrm{200}\:{days} \\ $$$$\mathrm{1}\:{woman}\:{in}\:\mathrm{1}\:{day}\:=\:\frac{\mathrm{1}}{\mathrm{200}}\:{part}\:{of}\:{work} \\ $$$$\mathrm{4}\:{women}\:{in}\:\mathrm{1}\:{day}\:=\:\frac{\mathrm{4}}{\mathrm{200}}\:=\:\frac{\mathrm{1}}{\mathrm{50}}\:{part}\:{of}\:{work} \\ $$$$\mathrm{3}\:{men}\:{and}\:\mathrm{4}\:{women}\:{in}\:\mathrm{1}\:{day}\:=\:\frac{\mathrm{3}}{\mathrm{100}}+\frac{\mathrm{1}}{\mathrm{50}}=\frac{\mathrm{1}}{\mathrm{20}}\:{part}\:{of}\:{work} \\ $$$${so}\:\mathrm{3}\:{men}\:{and}\:\mathrm{4}\:{women}\:{can}\:{complete}\:{the}\:{work}\:{in}\:\mathrm{20}\:{days} \\ $$