371. A rectangular field 30 m long and 20 m broad. How much deep it should be dug so that from the earth taken out, a platform can be formed which is 8 m long, 5.5 m broad and 1.5 m high where as the earth taken out is increase by 10/5?

✅ The correct answer is option B. 10 cm.
30 * 20 * x = (8 * 5.5 * 1.5)/2