1. A boy walking at a speed of 10 km/h reaches his school 12 min late. Next time at a speed of 15 km/h reaches his school 7 min late. Find the distance of his school from his house?
2. A boat travels 30 km upstream in 5 hours and 100 km downstream in 10 hours. Find the speed of the boat in still water and the speed of the stream in km/hr.
3. The speed of a boat in still water is 15 km/h and the rate of stream is 5 km/h. The distance travelled downstream in 24 minutes is
4. Mohan covers a distance of 150 m in a certain time. If he increases his speed to 4 times his original speed, the time taken reduces by 30 seconds. Find the original time taken.
5. A boy walks from his home to school at 9 kmph, reaches the school 12 minutes early. If he walks from his home to school at 6 kmph, he reaches the school 6 minutes late. Find the time taken by him to go to school if he walks at 12 kmph.
6. The distance between two points P and Q is 115 km. Two persons start at the same time but one travelling from P towards Q and the other travelling from Q towards P. If their respective speeds are 40 kmph and 52 kmph, where do they meet each other?
7. A train, after moving 70 kms meets with an accident and its speed becomes ¾ of the normal speed, hence it reached the destination 38 min late. Had the accident been at 85 km from the starting place, the train would have been late only by 26 min late. Find the normal speed of the train in Km/hr.
8. Two swimmers A and B start swimming from the two opposite ends of a swimming pool. First time they cross each other at a point 20 m from the shallow end. Second time they cross each other at a point 8 m from the deep end. Find the length of the swimming pool.
9. A train travelling at 70 kmph, crosses a cyclist who is cycling at 10 kmph in the opposite direction in 25 sec. Find the time taken by the train to cross another cyclist travelling at 20 kmph in the same direction as the train does.
10. Two boats travelling at 5km/h and 10km/hr, head directly towards each other. They begin at a distance of 20 kms from each other. How far apart are they (in kms) one minute before they collide?