AP ICET 2017 Shift 2 Paper

A train travels at a speed of 40 kmph through turban areas. 50 kmph in suburban areas and 75 kmph in rural areas. If the trip of train has half-an-hour travel in urban areas.$3\frac{1}{2}$ hours through suburban areas and 3 hours in rural areas then the average speed (in kmph) of the train during the entire trip is