Question

A = 15/1.4 + 15/4.7 + 15/7.10+...+15/61.64 =?

Answer 1

A = \(\dfrac{15}{1.4}\) + \(\dfrac{15}{4.7}\) + \(\dfrac{15}{7.10}\) + ... + \(\dfrac{15}{61.64}\)

A = \(5.\left(\dfrac{3}{1.4}+\dfrac{3}{4.7}+\dfrac{3}{7.10}...+\dfrac{3}{61.64}\right)\)

A = 5.( \(\dfrac{1}{1}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{7}\) + \(\dfrac{1}{7}\) - \(\dfrac{1}{10}\) + ... + \(\dfrac{1}{61}\) - \(\dfrac{1}{64}\))

A = 5.( \(\dfrac{1}{1}\) - \(\dfrac{1}{64}\))

A = 5. \(\dfrac{63}{64}\)

A = \(\dfrac{315}{64}\)