Question

R = 5 / 11 * 16 + 5 / 16 * 21 + ...+ 5 / 61 * 66

Answer 1

R = 5 / 11 * 16 + 5 / 16 * 21 + ...+ 5 / 61 * 66

= 1/11 - 1/16 + 1/16 - 1/21 + ... + 1/61 - 1/66

= 1/11 - 1/66

= 5/66

Answer 2

\(R=\frac{5}{11.16}+\frac{5}{16.21}+...+\frac{5}{61.66}\)

\(R=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+...+\frac{1}{61}-\frac{1}{66}\)

\( R=\frac{1}{11}-\frac{1}{66}=\frac{6}{66}-\frac{1}{66}=\frac{5}{66}\)

Answer 3

\(R=\frac{5}{11\times16}+\frac{5}{16\times21}+\frac{5}{61\times66}\)

\(=\frac{1}{11}-\frac{1}{16}+\frac{1}{16}-\frac{1}{21}+.....+\frac{1}{61}-\frac{1}{66}\)

\(=\frac{1}{11}-\frac{1}{66}=\frac{6}{66}-\frac{1}{66}=\frac{5}{66}\)