How weather the given question is hcf or lcm

1.	How weather the given question is hcf or lcm
Answer» whenever you are required to find a number that is\xa0divisible\xa0by more than one number, you have to find LCM.whenever you are required to find a number that\xa0completely divides\xa0more than one number, you have to find HCF.Coming to illustrative examples\xa0:LCMThree traffic signals change from Red to Green in 10, 15 & 20 seconds respectively. After how much time will all three signals together become Green ?The three traffic signals will change from Red to Green as follows ( in seconds ):First : 10,20,30,40,50,60,70,80 …..Second : 15,30,45,60,75,90 …Third : 20,40,60,80 …It is clear the three signals will flash Green together after 60 seconds. Now , this 60 is completely\xa0divisible\xa0by 10, 15 & 20 and LCM(10, 15 , 20) is 60, hence the problem was of finding LCM.HCFSquare towels has to be cut from a piece of cloth measuring 16m x 20m. What is the minimum number of towels that can be cut so that there is no wastage ?\xa0The towels are square and length is equal to width. Since there should be no wastage, the edge of the towel should exactly divide the length & breadth of the piece of cloth. The dimension of the towel is that highest number which completely divides 16 & 20. So, here we have a case of HCF.HCF(16,20) = 4So, the dimension of towel is 4m x 4mThe minimum number of towels possible is (16 x 20 )/ (4 x 4) = 20.

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