Letters

proteek

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Jun 28, 2020
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S sends a letter to R every day (every 24 hours). However R receives a letter every 25 hours. How many letters will R have have received by the 25th day?
 

Subhotosh Khan

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S sends a letter to R every day (every 24 hours). However R receives a letter every 25 hours. How many letters will R have have received by the 25th day?
When does the day count begin - with 'S' sending the first letter or 'R' receiving the first letter?

Please show us what you have tried and exactly where you are stuck.​
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Please share your work/thoughts about this assignment.​
 

HallsofIvy

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Jan 27, 2012
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This can be done by "dimensional analysis". There are 24 hours/day, which has "days" in the denominator, and 25 days has "days" in the numerator, so we can go from "days" to "hours" by multiplying: there are (24 hours/day)(25 days)= (24)(25) hours.

If postal people are willing to deliver at 1 or 2 in the morning and he gets a letter every 25 hours, there 25 hours/letter. We need to cancel "hours" and get "letters" Since "letters" is in the denominator we need to "invert" "hours/letter"- we need to divide (24)(25) hours by 25 hours per letter giving (24)(25)/25= 24 letters.
 

Jomo

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Dec 30, 2014
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Alternatively, there are 25*24 hours = 600 hours in 25 days. How many 25 hrs are in 600hrs? There are 24 of them, so R will receive 24 letters
 
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