Wikipedia:Reference desk/Archives/Mathematics/2011 September 5

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September 5

make all sums

Hi. I'm looking at the numbers that you cannot make out of adding nonnegative integer multiples of two integers. Take n=5,m=6 as an example. The largest number X for which you can't solve the equation an+bm=X (with a,b nonnegative integers) is 19, I think. What's the proper name for this problem? Robinh (talk) 02:51, 5 September 2011 (UTC)

This is the coin problem.--Antendren (talk) 03:51, 5 September 2011 (UTC)

Resolved

. Thank you! Robinh (talk) 09:37, 5 September 2011 (UTC)

word problem

A T-shirt cost 5 times as much a singlet.With $800, I can buy 32 more singlets than shirts.What is the cost of a shirt? — Preceding unsigned comment added by Agdesi (talk • contribs) 06:20, 5 September 2011 (UTC)

Do you mean "T = 5S" and "800 = nT" and "800 = (32+n)S" ? And are you asking us to solve for T ? If so, try solving for n first. StuRat (talk) 07:44, 5 September 2011 (UTC)

Note also that the Ref desks have a policy of not doing people's homework for them -- although we may be able to give a helpful hint if you tell us what you have tried and where you got stuck. Looie496 (talk) 15:37, 5 September 2011 (UTC)

Yes, like the set-up I provided. StuRat (talk) 16:10, 5 September 2011 (UTC)