A boat goes 15 km upstream and 10 1/2 km down stream in 3 hrs 15 min. It goes 12 km upstream and 14 km downstream in 3 hrs. What is the speed of the boat in still water?
A cone is hollowed out of a solid wooden cube of side 7 cm. The diameter and height of the cone is same as the side of the cube. What is the volume of the remaining cube?
By increasing the price of entry ticket to a fair in the ratio 5:7, the number of visitors to the fair has decreased in the ratio 11:9. In what ratio has the total collection increased or decreased?