A student walks from his house at a speed of 2 12 K per hour and reaches his school 6 minutes late. The next day he increases his speed by 1 km per hour and reaches 6 minutes before school time. How far is the school from his house?
At what profit percent must an article be sold so that by selling at half that price, there will be a loss of 30%?
A boat covers 143 km upstream in 13 hours and the same distance downstream in 11 hours. What is the speed (in km / hr ) of the boat in still (without stream) water?
10 km/hr
12 km/hr
14 km/hr
8 km/hr
The speed of three cars is in the ratio of 2 : 3 : 4 . The ratio of the times taken by these cars to travel the same distance is -