1 / 2 * 5 + 1 / 5 * 8 + 1 / 8 * 11 + 1 / 11 * 14 + 1 / 14 * 17

1 / 2 * 5 + 1 / 5 * 8 + 1 / 8 * 11 + 1 / 11 * 14 + 1 / 14 * 17

1 / (2 * 5) + 1 / (5 * 8) + 1 / (8 * 11) + 1 / (11 * 14) + 1 / (14 * 17)
= (1 / 3) [(1 / 2 - 1 / 5) + (1 / 5 - 1 / 8) + (1 / 8 - 1 / 11) + (1 / 11 - 1 / 14) + (1 / 14 - 1 / 17)]
= (1 / 3) (1 / 2 - 1 / 17)
= 5 / 34