To fill a tank measuring 60 cm by 30 cm by 20 cm completely, it takes Tap M 4 minutes while it takes Tap N only 16 minutes. How long will it take to completely fill the container with water if both the taps are turned on at the same time and 5 cubic containers of edges 6 cm, filled to the brim with water are poured into the tank?
Volume of the tank 
= 60 x 30 x 20
= 36000 cm³

Volume of 5 containers
= 6 x 6 x 6 x 5
= 1080 mℓ

Remaining volume to be filled by the Tap M and Tap N 
= 36000 - 1080
= 34920 mℓ
= 34920 cm³

Fraction of the tank to be filled
= ³⁴⁹²⁰₃₆₀₀₀
= ⁹⁷₁₀₀

Tap M:
1 tank → 4 min
1 min → ¹₄ tank

Tap N:
1 tank → 16 min
1 min → ¹₁₆ tank

Tap M and Tap N:
1 min → ¹₄ + ¹₁₆ = ⁴₁₆ + ¹₁₆ = ⁵₁₆ tank
1 tank → ¹⁶₅ min

⁹⁷₁₀₀ tank → ¹⁶₅ x ⁹⁷₁₀₀ = ³⁸⁸₁₂₅ = 3.104 min

Answer(s): 3.104 min