ramanbajwa2003 wrote:

amanvermagmat wrote:

you are correct that LCM of fractions = (LCM of numerators)/(HCF of denominators)

Now lets write the given numbers as fractions:

66.6666... (recurring) = 66 2/3 = 200/3

50 = 50/1

so LCM = (LCM of 50 & 200)/(HCF of 3 & 1) = 200/1 = 200

I think you are probably shortening the recurring decimal 66.6666... to 66.66 and hence this mismatch

Thanks! You made it look simple and I understood my mistake here. I was considering it to be non-recurring decimal places and the dividing the whole number by 100 to remove the decimal.

Now coming back to the actual question(below), how can I assume here that the decimal is recurring ? Did I miss a trick or assumption ?

"There are two bells in a temple. Both the bells toll at a regular interval of 66.66 sec and 50 sec respectively. After how much time will they toll together for the first time?"

Well the question doesn't state that its recurring, it just writes 66.66. But in such cases its mostly better to assume recurring because then we can easily convert them to decimal. I suggest if answer options are in integers then you assume the decimal to be recurring only.

But yes ideally the question should have specified that it was a recurring decimal.