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Bunuel
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Bunuel
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Hi Bunuel! Thank you for the solution.

I have a doubt in such questions and would really appreciate if you could help clarify the same or share any similar examples with me.
I calculated the LCM and got 12, however, I was unsure of the two following things-
1. Should I start counting days from Monday or Tuesday?
2. Will the 12th day be the answer or the day right after the 12th day ends (Sunday) will be the answer?

Thank you
Bunuel
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Deborah and Mike regularly visit the university library every 3 and 4 days, respectively. If they both were at the library on a Monday, on which day of the week will they both be in the library together the next time?

A. Wednesday
B. Thursday
C. Friday
D. Saturday
E. Sunday


Deborah and Mike will meet in the library again after 12 days, as it is the least common multiple of their respective visiting intervals, 3 and 4 days. Therefore, their next encounter will occur on a Saturday, which is 12 days after the initial Monday meeting.


Answer: D
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Anjummm1
Hi Bunuel! Thank you for the solution.

I have a doubt in such questions and would really appreciate if you could help clarify the same or share any similar examples with me.
I calculated the LCM and got 12, however, I was unsure of the two following things-
1. Should I start counting days from Monday or Tuesday?
2. Will the 12th day be the answer or the day right after the 12th day ends (Sunday) will be the answer?

Thank you
Bunuel
Official Solution:

Deborah and Mike regularly visit the university library every 3 and 4 days, respectively. If they both were at the library on a Monday, on which day of the week will they both be in the library together the next time?

A. Wednesday
B. Thursday
C. Friday
D. Saturday
E. Sunday


Deborah and Mike will meet in the library again after 12 days, as it is the least common multiple of their respective visiting intervals, 3 and 4 days. Therefore, their next encounter will occur on a Saturday, which is 12 days after the initial Monday meeting.


Answer: D

Here’s how you can resolve your doubt. Pick smaller numbers, like 2 and 3. The LCM is 6. Now, list the days the first person would visit the library and the days the second person would visit. Find the day they both meet again. Then check whether that day is 6 days from Monday or 6 days from Tuesday. This should clear things up for you.
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The LCM of 3 and 4 is 12, 24,
Say Monday is day 12 then day 24 would be on Satuday
M - T - W - T - F - S - S
12 (week 1)
19 -20-21-22-23-24
So, the next 12 day is Saturday (D)
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