Answer:
semoga jawapan ini dapat membantu
What is the book? Show an image please.. I would love to help!
I would find the common factors between all of them, and settle with the factor 3.
If I have 3 tanks:
12/3 = 4
24/3 = 8
30/3 = 10
In each of the 3 tanks, there will be 4 angel fish, 8 sword fish, and 10 guppies.
I hope I helped :)
(I hope I didn't misunderstand the question, so if I did, I'm really sorry about that.)
3 pipes take 12 hours
⇒ In 1 hour, the 3 pipes can fill 1/12 of the pool
2 of the pipes take 18 hours
⇒ in 1 hour, the 2 pipes can fill 1/18 of the pool
In 1 hour, the third pipe alone can fill :

Time needed :

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Answer: It will take 36 hours for the third pipe to fill the pool.----------------------------------------------------------------------------------------