Linear cubics

The sum 3123+5234+7345++81404142 \frac{3}{1 \cdot 2 \cdot 3} + \frac{5}{2 \cdot 3 \cdot 4} + \frac{7}{3 \cdot 4 \cdot 5} + \cdots + \frac{81}{40 \cdot 41 \cdot 42} can be expressed as ab \frac{a}{b} where aa and bb are coprime positive integers. What is the value of a+ba + b?

×

Problem Loading...

Note Loading...

Set Loading...