Cannot understand a solution to evaluating $C_{2}^{2000}+C_{5}^{2000}+C_{8}^{2000}+\cdots+C_{2000}^{2000}$

Asked Mar 27 '21 at 07:03

Active Mar 27 '21 at 07:27

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There is a problem in the book 101 Problems in Algebra which is:

Evaluate this $$C_{2}^{2000}+C_{5}^{2000}+C_{8}^{2000}+\cdots+C_{2000}^{2000}$$

I cannot understand the solution (shown below) to this problem. How can the statement is equal to the next line in the green marked box? Can anyone make me understand?

edited Mar 27 '21 at 07:27

Blue

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asked Mar 27 '21 at 07:03

Alavi Al Anjum Sifat

2

Mark Bennet's and Yiorgos S. Smyrlis's answers will show you why the equation is true. – player3236 Mar 27 '21 at 07:26

Cannot understand a solution to evaluating $C_{2}^{2000}+C_{5}^{2000}+C_{8}^{2000}+\cdots+C_{2000}^{2000}$

0 Answers0