To fill a tank measuring 40 cm by 40 cm by 20 cm completely, it takes Tap J 8 minutes while it takes Tap K 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 8 cubic containers of edges 10 cm, filled to the brim with water are poured into the tank?
Volume of the tank 
= 40 x 40 x 20
= 32000 cm³

Volume of 8 containers
= 10 x 10 x 10 x 8
= 8000 mℓ

Remaining volume to be filled by the Tap J and Tap K 
= 32000 - 8000
= 24000 mℓ
= 24000 cm³

Fraction of the tank to be filled
= ²⁴⁰⁰⁰₃₂₀₀₀
= ³₄

Tap J:
1 tank → 8 min
1 min → ¹₈ tank

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

Tap J and Tap K:
1 min → ¹₈ + ¹₁₂ = ³₂₄ + ²₂₄ = ⁵₂₄ tank
1 tank → ²⁴₅ min

³₄ tank → ²⁴₅ x ³₄ = ¹⁸₅ = 3.6 min

Answer(s): 3.6 min