Distance between two stations A and B is 778 km. A train covers the journey from A to B at 84 km per hour and returns back to A with a uniform speed of 56 km per hour. Find the average speed of the train during the whole journey.
A batsman makes a score of 87 runs in the 17 th inning and thus increases his average by 3 . Find his average after 17th inning.
There were 35 students in a hostel. Due to the admission of 7 new students the expenses of the mess were increased by Rs. 42 per day while the average expenditure per head diminished by Re. 1 What was the original expenditure of the mess ?
The average weight of 10 oarsmen in a boat is increased by 1.8 kg When one of the crew, who weights 53 kg is replaced by a new man. Find the weight of the new man .
The average age of a class of 39 students is 15 years . If the age of the teacher be included, then the average increases by 3 months. Find the age of he teacher..