Telangana PSC Group 4 Secretarial Ability 2018 Paper 2

Three pipes A, B and C are available to fill a tank. The time taken to fill the tank by A is 15 hours and by B is 10 hours. The time taken to fill the tank by both A and B together is equal to the time required for C to fill it. How much time is required to fill the tank by all the three pipes together?