Barb, Shelley, and Darcy are college roommates. Barb goes to the library every 6 days, Shelley goes the library every 7 days, an
d Darcy goes to the library every 4 days. If all three of them went to the library today, when is the next time that they will all be at the library on the same day?
If all three of them went to the library today, then the next time that they will all be at the library on the same day will be the LCM of 6,7, and 4 i.e.on 84th day.</span>
So the equation is n/4-4=14 then you +4 to both sides n/4-4=14 so now the equation is n/4=18 then you multiply 18 by 4 and get 72 +4 +4 then to check your work 72/4-4=14 so N=72 Hope I helped :)