question_answer

7 pipes attached with a tank out of which some are inlets and outlets. Every inlet can fill tank in 10 hours and every outlet can empty tank in 15 hours when all the pipes are opened simultaneously the tank filled up \[\frac{30}{11}\] hours. Find the no. of inlets & outlets-

A) 5, 2

B) 2, 5

C) 3, 4

D) 4, 3

E) None of these