`C = 5/21.28 + 5/28.35 + ... + 5/707.714`
`C = 5 . (1/21.28 + 1/28.35 + ... + 1/707.714)`
`C = 5/7 . (7/21.28 + 7/28.35 + ... + 7/707.714)`
`C = 5/7 . (1/21 - 1/28 + 1/28 - 1/35 + ... + 1/707 - 1/714)`
`C = 5/7 . (1/21 - 1/714)`
`C = 5/7 . 11/238`
`C = 55/1666.`