To fill a tank measuring 40 cm by 40 cm by 40 cm completely, it takes Tap U 8 minutes while it takes Tap V 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 8 cm, filled to the brim with water are poured into the tank?
Volume of the tank 
= 40 x 40 x 40
= 64000 cm³

Volume of 5 containers
= 8 x 8 x 8 x 5
= 2560 mℓ

Remaining volume to be filled by the Tap U and Tap V 
= 64000 - 2560
= 61440 mℓ
= 61440 cm³

Fraction of the tank to be filled
= ⁶¹⁴⁴⁰₆₄₀₀₀
= ²⁴₂₅

Tap U:
1 tank → 8 min
1 min → ¹₈ tank

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

Tap U and Tap V:
1 min → ¹₈ + ¹₁₂ = ³₂₄ + ²₂₄ = ⁵₂₄ tank
1 tank → ²⁴₅ min

²⁴₂₅ tank → ²⁴₅ x ²⁴₂₅ = ⁵⁷⁶₁₂₅ = 4.608 min

Answer(s): 4.608 min