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SMO 2014 Senior Round 1 Question 16

SMO · SMO 2014 Senior Round 1

Question 16

Evaluate the sum $$\frac{3!+4!}{2(1!+2!)}+\frac{4!+5!}{3(2!+3!)}+\cdots+\frac{12!+13!}{11(10!+11!)}.$$