a woman do a piece of work in 20 days, and another woman can do it in 30 days. How long will they take if both work together

[tex] \frac{1}{20} + \frac{1}{30} = \frac{3 + 2}{60} = \frac{5}{60} \\ [/tex]
waktu yang dibutuhkan jika mereka bekerja sama = 60 ÷ 5 = 12 hari (12 days)
sorry i'm not fluent in english so i answer it in bahasa hope it can help u :)