6. Janica and Jelica need 30 hours to translate a certain number of pages of text, Janica and Jurica need 42 hours, and Jelica and Jurica will finish the translation in 35 hours. How much time (hours and minutes) would they need for this translation if all three worked together?
6. Since Janica and Jelica need 30 hours to translate a certain number of pages of text, it follows that the two of them together will translate $\frac{1}{30}$ of the text in 1 hour. In the same way, Janica and Jurica will translate $\frac{1}{42}$ of the pages of text in 1 hour, and Jelica and Jurica $\frac{1}{35}$.

3 POINTS

If all three worked together, they would translate in 1 hour

$$
\left(\frac{1}{30}+\frac{1}{42}+\frac{1}{35}\right): 2=\frac{7+5+6}{5 \cdot 6 \cdot 7} \cdot \frac{1}{2}=\frac{18}{5 \cdot 6 \cdot 7} \cdot \frac{1}{2}=\frac{3}{70}
$$

The entire text would be translated in $x$ hours, so the equation is $x \cdot \frac{3}{70}=1 \Rightarrow x=\frac{70}{3}=23 \frac{1}{3}$.

Therefore, if all three worked together on the translation, the job would be completed in 23 hours and 20 minutes.