Question

a water tank has three inlets. inket 1 alond can fill in 30 min. inlet 2 can fill in 40 mins. 3 can fill in 60 mins. if theyre opened together, how lobg it will take to fill


challenge to mods and stars​

Answer 1

Answer:

13.3 minutes

Step-by-step explanation:

A alone can fill the tank in 30 minutes.

A's 1 hour work = \frac{1}{30}301

B can fill it in 40 minutes

B's 1 hour work = \frac{1}{40}401

C can fill it in 60 minutes.

C's 1 hour work = \frac{1}{60}601

They work together in 1 hour = \frac{1}{30}+\frac{1}{40}+\frac{1}{60}301+401+601

                                                 = \frac{3}{40}403  

If they work together it will take time to fill the tank= \frac{40}{3}=13.33340=13.33  

Hence it will take 13.3 minutes to fill the tank if they work together

Answer 2

Correct question :-

A water tank has three inlets. Inlet 1 alone can fill the tank in 30 minutes. Inlet 2 can fill the tank in 40 minutes. Inlet 3 can fill the tank in 60 minutes. If all three are opened together, how long it will take to fill the tank?

Solution:-

Inlet 1 fills the tank in 30 minutes. Thus in 1 minute it'll fill :- 1÷30

Inlet 2 fills the tank in 40 minutes. Thus in 1 minute it'll fill :- 1÷40

Inlet 1 fills the tank in 60 minutes. Thus in 1 minute it'll fill :- 1÷60

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If the three inlets are opened together then in 1 minute they'll fill :-

$1 \div 30 + 1 \div 40 + 1 \div 60$

$4 + 3 + 2 \div 120$

$9 \div 120$

Since 9/120 of the tank can be filled in one minute, the whole tank will be filled in 120÷9 ( reciprocal the terms )

$120/9 = 40/3 \: minutes$

40/3 = 13 minutes and 20 seconds.

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