30 workers can dig a trench in 5 days. How many workers will be required to dig it in 6 days?

Workers required to dig in 5 days = 30 workers.

Workers required to dig in 1 day = (30 x 5) workers. $\quad$ [Less days, More workers]

Workers required to dig in 6 days = $\Big(\dfrac{30 \times 5}{6}\Big) \text{ workers} \quad \text{[More days, Less workers]}$

= (5 x 5) workers $\quad$ [Dividing 30 and 6 by 6]

= 25 workers.

25 workers are required to dig in 6 days.