maths problem

td1

.. a man can drink a barrel of beer in 27 days, a woman can drink it in 54. If they drink one together how long does it take them?

The man drinks beer at a rate that is twice that of the woman's rate of consumption: 2:1. So, when the barrel is empty, the man will have drank 2/3rds and the woman 1/3rd. 2/3rds of 27 is 18; 1/3rd of 54 is 18. So it would take 18 days for them both to finish off the barrel...

bnt

So one barrel takes 27 "man-days" of drinking work.
If the man and woman drink together, how many "man-days" of drinking can they do per (real) day?

1.5

Then 27 "man-days" divided by that many "man-days per day" gets you the result.

HansHolzel

x = barrel

x/27 = man's daily consumption

x/54 = woman's daily consumption

x/27 + x/54 = 3x/54 = x/18 = daily consumption of both together

Therefore it takes them 18 days to empty it.

BUT PROJECT MATHS MAY TELL YOU TO WATCH OUT FOR THE HANGOVERS! :-D

MathsManiac

HansHolzel wrote: »

BUT PROJECT MATHS MAY TELL YOU TO WATCH OUT FOR THE HANGOVERS! :-D

Indeed, project maths encourages you to always bring your answer back to the context, evaluate whether it's reasonable, and consider aspects of the model that may might result in the actual result being different from the one given by the model.

In this context, perhaps one ought to consider that a man and a woman drinking a barrel of beer together might get ...em... distracted in a manner that mightn't arise if either were drinking alone!

HansHolzel

MathsManiac wrote: »

Indeed, project maths encourages you to always bring your answer back to the context, evaluate whether it's reasonable, and consider aspects of the model that may might result in the actual result being different from the one given by the model.

In this context, perhaps one ought to consider that a man and a woman drinking a barrel of beer together might get ...em... distracted in a manner that mightn't arise if either were drinking alone!

One or both might fall in?