To fill a tank measuring 70 cm by 50 cm by 40 cm completely, it takes Tap X 6 minutes while it takes Tap Y only 14 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 10 cubic containers of edges 10 cm, filled to the brim with water are poured into the tank?
Volume of the tank 
= 70 x 50 x 40
= 140000 cm³

Volume of 10 containers
= 10 x 10 x 10 x 10
= 10000 mℓ

Remaining volume to be filled by the Tap X and Tap Y 
= 140000 - 10000
= 130000 mℓ
= 130000 cm³

Fraction of the tank to be filled
= ¹³⁰⁰⁰⁰₁₄₀₀₀₀
= ¹³₁₄

Tap X:
1 tank → 6 min
1 min → ¹₆ tank

Tap Y:
1 tank → 14 min
1 min → ¹₁₄ tank

Tap X and Tap Y:
1 min → ¹₆ + ¹₁₄ = ⁷₄₂ + ³₄₂ = ⁵₂₁ tank
1 tank → ²¹₅ min

¹³₁₄ tank → ²¹₅ x ¹³₁₄ = ³⁹₁₀ = 3.9 min

Answer(s): 3.9 min