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Evaluate the sum (Posted on 2018-12-01) Difficulty: 4 of 5
252+403+574+...+4606+3640+...+...+7663+8722=Sn

Find the logic beyond the summands in the above equation
and derive the values of n and Sn .

  Submitted by Ady TZIDON    
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Solution: (Hide)
a(n)= (two digit number) * (its reverse) i.e. (10p+r)*(10r+p);
p,r non zero digits r>p

n=36 S(n)=110,670

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Solutionsolution based on previous commentsCharlie2018-12-02 14:05:51
Hints/Tipsre(3): Solution Good thinking, wrong answerAdy TZIDON2018-12-02 08:57:50
re(2): Solution Good thinking, wrong answerbroll2018-12-02 06:35:12
Hints/Tipsre: Solution Good thinking, wrong answerAdy TZIDON2018-12-02 05:02:30
SolutionSolutionbroll2018-12-01 21:25:34
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