CDS Model Paper 3 Mathematics

Train A running at 60‌km∕h leaves Mumbai for Delhi at 6p.m. Train B running at 90‌km∕h also leaves for Delhi at 9 p.m. Train C leaves Delhi for Mumbai at 9 p.m. If all the three trains meet at the same time between Mumbai and Delhi, then what is the speed of train C, if distance between Delhi and Mumbai is 1260‌km ?