2 women and 5 men can together finish a piece of embroidery in 4 days, while 3 women and 6 men can finish it in 3 days. Find the time taken by 1 woman alone to finish the embroidery, and that taken by 1 man alone.
1 women alone can finish the work in $x$ days and 1 man alone can finish it in $y$ days then
One woman one day work $=\frac{1}{x}$
One man one days work $=\frac{1}{y}$
2 women's one days work $=\frac{2}{x}$
5 man's one days work $=\frac{5}{y}$
Since 2 women and 5 men can finish the work in 4 days
$4\left(\frac{2}{x}+\frac{5}{y}\right)=1$
$\frac{8}{x}+\frac{20}{y}=1 \cdots(i)$
3 women and 6 men can finish the work in 3 days
$3\left(\frac{3}{x}+\frac{6}{y}\right)=1$
$\frac{9}{x}+\frac{18}{y}=1 \cdots(i i)$
Putting $\frac{1}{x}=u$ and $\frac{1}{y}=v$ in equation $(i)$ and $(i i)$ we get
$8 u+20 v-1=0 \cdots(i i i)$
$9 u+18 v-1=0 \cdots(i v)$
By using cross multiplication we have
$\frac{u}{(20 \times-1)-(18 \times-1)}=\frac{-v}{(8 \times-1)-(9 \times-1)}=\frac{1}{(8 \times 18)-(9 \times 20)}$
$\frac{u}{-20+18}=\frac{-v}{-8+9}=\frac{1}{144-180}$
$\frac{u}{-2}=\frac{-v}{1}=\frac{1}{-36}$
$u=\frac{1}{18}$
$v=\frac{1}{36}$
Now ,
$u=\frac{1}{18}$
$\frac{1}{x}=\frac{1}{18}$
$x=18$
$v=\frac{1}{60}$
$\frac{1}{y}=\frac{1}{60}$
$y=60$
Hence, the time taken by 1 woman alone to finish the embroidery is 36 days,
The time taken by 1 man alone to finish the embroidery is 18 days.