Question Number 190781 by Tawa11 last updated on 11/Apr/23
Commented by mr W last updated on 11/Apr/23
$${if}\:{you}\:{understand}\:{the}\:{question},\:{then} \\ $$$${you}\:{should}\:{be}\:{able}\:{to}\:{solve}\:{it}.\:{i}\:{don}'{t} \\ $$$${understand}\:{the}\:{question},\:{so}\:{i}\:{can}'{t} \\ $$$${solve}\:{it}.\:{i}\:{don}'{t}\:{understand}\:{it},\:{because} \\ $$$${it}'{s}\:{not}\:{clear}.\:{a}\:{question}\:{which}\:{is} \\ $$$${not}\:{uniquely}\:{clear},\:{is}\:{a}\:{wrong}\:{question}. \\ $$
Answered by ajfour last updated on 11/Apr/23
$$\mathrm{20}{boys}\equiv\mathrm{3}{men} \\ $$$${so}\:\mathrm{4}{hours}\rightarrow\:\mathrm{6}{men} \\ $$$$\mathrm{2}{hours}\rightarrow\mathrm{12}{men} \\ $$
Commented by ajfour last updated on 11/Apr/23
https://youtu.be/WGRDv1fYlh4 A mishap creating a projectile motion question
Commented by Tawa11 last updated on 28/Apr/23
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$
Answered by mr W last updated on 12/Apr/23
$${as}\:{i}\:{have}\:{said}\:{the}\:{question}\:{is}\:{not}\:{clear}. \\ $$$${one}\:{possiblity}\:{is}: \\ $$$$\mathrm{3}\:{men}\:{and}\:\mathrm{20}\:{boys}\:{do}\:{a}\:{job}\:{in}\:\mathrm{4}\:{hours}. \\ $$$${the}\:{men}\:{do}\:\mathrm{20}/\mathrm{3}\:{times}\:{much}\:{as}\:{the}\: \\ $$$${boys}\:{do},\:{that}\:{means}\:{if}\:{the}\:\mathrm{3}\:{men}\:{do}\:{x}\: \\ $$$${job},\:{then}\:{the}\:\mathrm{20}\:{boys}\:{do}\:\frac{\mathrm{3}{x}}{\mathrm{20}}\:{job}. \\ $$$${x}+\frac{\mathrm{3}{x}}{\mathrm{20}}=\mathrm{1}\:\Rightarrow{x}=\frac{\mathrm{20}}{\mathrm{23}} \\ $$$${that}\:{means}\:\mathrm{3}\:{men}\:{do}\:\frac{\mathrm{20}}{\mathrm{23}}\:{job}\:{in}\:\mathrm{4}\:{hours}. \\ $$$${say}\:{each}\:{man}\:{do}\:{y}\:{job}\:{in}\:{one}\:{hour}, \\ $$$${then}\:{y}=\frac{\mathrm{20}}{\mathrm{23}×\mathrm{3}×\mathrm{4}}=\frac{\mathrm{5}}{\mathrm{69}}. \\ $$$${so}\:{to}\:{do}\:{the}\:{job}\:{in}\:\mathrm{2}\:{hours}\:{we}\:{need} \\ $$$$\frac{\mathrm{1}}{\mathrm{2}×\frac{\mathrm{5}}{\mathrm{69}}}=\mathrm{6}.\mathrm{9}\approx\mathrm{7}\:{men}. \\ $$
Commented by Tawa11 last updated on 28/Apr/23
$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$