Man1 does a work in 10 days and Man2 does the same work in 15 days. In how many days they together will do the same work ?  Choices:
A) 10 days B) 5 days C) 6 days D) 7 days E) 8 days

Rationale: man 1 day work = 1 / 10 man 2 day work = 1 / 15 both work = 1 / 10 + 1 / 15 = = = > 3 + 2 / 30 = = > 1 / 6 answer c
Answer: C