Explanation

To solve this problem, we can calculate the rate at which the laborers dig the earth:

Rate = 805 cubic meters / (35 laborers × 5 hours)

= 805 / 175

= 4.6 cubic meters per laborer per hour

Now, we can calculate the amount of earth dug by 30 laborers in 6 hours:

Earth dug = 30 laborers × 6 hours × 4.6 cubic meters per laborer per hour

= 30 × 6 × 4.6

= 828 cubic meters

The correct answer is 828m³.