Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion

 September 7th, 2019, 01:34 PM #1 Senior Member   Joined: Dec 2015 From: Earth Posts: 827 Thanks: 113 Math Focus: Elementary Math Equation with natural variable $\displaystyle \lfloor n/1 \rfloor + \lfloor n/2 \rfloor +...+\lfloor n/(n-1) \rfloor =7\;$, n-natural . To write it better : $\displaystyle \sum_{j=1}^{n-1} \displaystyle \lfloor \frac{n}{j} \displaystyle \rfloor =7 \;$ ; n=? , Method Required ! Last edited by idontknow; September 7th, 2019 at 01:38 PM. September 8th, 2019, 03:27 AM #2 Senior Member   Joined: Dec 2015 From: Earth Posts: 827 Thanks: 113 Math Focus: Elementary Math $\displaystyle m_1 =\lfloor 7/2 \lfloor$ and $\displaystyle m_{2} =1+m_1$. $\displaystyle M=\frac{1+2m_1 }{2}=3,5$. Number of elements is $\displaystyle \lfloor 3,5 \rfloor =3$ which is n+1 .So $\displaystyle n=4$. To verify : +[4/2]+[4/3] =4+2+1=7 . Tags equation, natural, variable Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post idontknow Number Theory 8 January 28th, 2017 04:24 AM mhhojati Linear Algebra 3 January 20th, 2017 05:41 AM Silly Moo Calculus 1 March 2nd, 2015 03:38 PM BrianMX34 Algebra 5 September 8th, 2012 09:04 AM Zaeem Algebra 2 January 11th, 2011 04:39 AM

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