Radha and Mohan's average age is 75 years. The average age of Radha, Mohan and Jay is 55 years. What is the age of Jay?

15 years

Average age of Radha & Mohan = 75 years

Total age of Radha & Mohan = 75 × 2 = 150 years

Average age of Radha, Mohan & Jay = 55 years

Total age of Radha, Mohan & Jay = 55 × 3 = 165 years

Jay age = (Total age of Radha, Mohan & Jay) - (Total age of Radha & Mohan) = 165 - 150 = 15 years