Some men can do a piece of work in 60 days. If 8 more men join them the work is finished 10 days before the stipulated time. How many men were there in the beginning?

Two trains 160 meter long and 140 m long respectively run at the rate of 77 kmph and 67 kmph respectively in opposite directions on parallel tracks. How long do they take to pass each other?

In what proportion must some tea at Rs. 60 per kg. be mixed with another tea at Rs. 65 per kg. so that the new mixture is sold at Rs. 68.2 per kg. at a profit of 10%?

The height of a right circular cylinder is 8 cm. Four times the sum of the area of its two circular faces is twice the area of its curved surface. The radius of the base is

Water flows in a tank whose base is 250m x 100m through a pipe whose cross-section is 3dm by 2.5dm at the speed of 20 km per hour. In what time will the water level rise to 1.5 metres?