A man rows from J to K (upstream) and back from K to J (downstream) in a total time of 15 hours. The distance between J and K is 300 km. The time taken by the man to row 9 km downstream is identical to the time taken by him to row 3 km upstream. What is the approximate speed of the boat in still water?

The width of the path around a square field is 4.5 m and its area is 105.75 m². Find the cost of fencing the path at the rate of ₹100 per metre.

The ratio of officers to soldiers in a regiment before the war was 3 : 31. 6 officers and 22 soldiers were killed in the war and the ratio became 1:13. What was the number of officers in the regiment before the war?

From a circle of radius a, a sector, which subtend an angle π/5 at the centre has been cut off. The perimeter of the remaining part of the circle is

12 kg of rice costing 30 per kg is mixed with 8 kg of rice costing 40 per kg. The average per kg price of mixed rice is

A reduction of 20% in the price of sugar enables a housewife to purchase 6 kg. more for Rs. 240. What is the original price per kg. of sugar?

The distance between the points (4, 8) and (k, -4) is 13. What is the value of k? 

A work is done by 30 workers not all of them have the same capacity to work. Every day exactly 2 workers, do the work with no pair of workers working together twice. Even after all possible pairs have worked once, all the workers together works for six more days to finish the work. Find the number of days in which all the workers together will finish the work?