Answer: 0.06 litre or 60 ml
Explanation:
Given: The capacity of glass tank= 26 liter
If he add 20.9 liters of water after 85 marbles to fill it completely, then
The volume of 85 marbles=

Since, the marbles have same volume.
∴ Volume of each marble=

⇒ Volume of each marble=

In milliliters, Volume of each marble=
