It takes Faucet S 40 minutes to fill a tank measuring 10 cm by 28 cm by 13 cm completely while it takes Faucet T only 35 minutes. How long will it take to completely fill the tank with water if both the faucets are turned on at the same time? Leave your answer in minutes and round off to 2 decimal places.
Volume of the tank
= 10 x 28 x 13
= 3640 cm³

Rate of Faucet S
40 min → 3640 cm³
1 min → 3640 ÷ 40 = 91 cm³/min

Rate of Faucet T
35 min → 3640 cm³
1 min → 3640 ÷ 35 = 104 cm³/min

Rate if both Faucet S and Faucet T are turned on together
= 91 + 104
= 195 cm³/min

Time taken to fill up the tank if both Faucet S and Faucet T are turned on together
= 3640 ÷ 195
≈ 18.67 min (Round off to 2 decimal places)

Answer(s): 18.67 min