For 4 h and 48 min. The first pipe fills the whole pool for 8 hours so from here we see that it fills 1/8 each hour. The second pipe fills it for 12 hours so it fills 1/12 each hour. Now both of them together fill 1/8 + 1/12 of the pool each hour. That equals: 1st pipe 3/24 of the pool each hour and the 2nd pipe 2/24 of the pool each hour. So, the two pipes together fill 3/24 + 2/24 each hour. That's 5/24 of the pool each hour. 1st hour: 5/24 2nd hour: 10/24 3rd hour: 15/24 4th hour: 20/24 And we need 4/24 more. So, if 5/24 is 1 h, then 1/24 is (60 minutes/5) 12 minutes. We need 4*1/24 and that is 12 minutes * 4 and that is 48 minutes.
False, because the number 40 is a composite number, those that cannot be broken down are called Prime Numbers.
Prime numbers are numbers that are used to decompose any number, but prime numbers cannot be decomposed, since they only have two Divisors, which are 1 and itself.
