To fill a tank measuring 40 cm by 20 cm by 30 cm completely, it takes Tap F 4 minutes while it takes Tap G only 12 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 10 cm, filled to the brim with water are poured into the tank?
Volume of the tank 
= 40 x 20 x 30
= 24000 cm³

Volume of 5 containers
= 10 x 10 x 10 x 5
= 5000 mℓ

Remaining volume to be filled by the Tap F and Tap G 
= 24000 - 5000
= 19000 mℓ
= 19000 cm³

Fraction of the tank to be filled
= ¹⁹⁰⁰⁰₂₄₀₀₀
= ¹⁹₂₄

Tap F:
1 tank → 4 min
1 min → ¹₄ tank

Tap G:
1 tank → 12 min
1 min → ¹₁₂ tank

Tap F and Tap G:
1 min → ¹₄ + ¹₁₂ = ³₁₂ + ¹₁₂ = ¹₃ tank
1 tank → ³₁ min

¹⁹₂₄ tank → ³₁ x ¹⁹₂₄ = ¹⁹₈ = 2.375 min

Answer(s): 2.375 min