To fill a tank measuring 70 cm by 70 cm by 48 cm completely, it takes Tap Y 42 minutes while it takes Tap Z only 28 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 7 cm, filled to the brim with water are poured into the tank? Leave your answer in minutes and round off to 2 decimal places.
Volume of the tank 
= 70 x 70 x 48
= 235200 cm³
= 235200 mℓ

Volume of 8 containers
= 7 x 7 x 7 x 8
= 2744 cm³ 
= 2744 mℓ

Remaining volume to be filled by the Tap Y and Tap Z 
= 235200 - 2744
= 232456 mℓ
= 232456 cm³

Fraction of the tank to be filled
= ²³²⁴⁵⁶₂₃₅₂₀₀
= ⁵⁹³₆₀₀

Tap Y:
1 tank → 42 min
1 min → ¹₄₂ tank

Tap Z:
1 tank → 28 min
1 min → ¹₂₈ tank

Tap Y and Tap Z:
1 min → ¹₄₂ + ¹₂₈ = ²₈₄ + ³₈₄ = ⁵₈₄ tank

1 tank = ⁸⁴₅ min

⁵⁹³₆₀₀ tank = ⁸⁴₅ x ⁵⁹³₆₀₀ = ⁴¹⁵¹₂₅₀ = 16.604

Answer(s): 16.60 min