A rectangular lot 50 feet by 100 feet is surrounded on all sides by a concrete walk 5 feet wide. Find the number of square feet in the surface of the walk.
A car that gets 15 miles per gallon of gasoline can travel 250 miles on a full tank. If the same car got 20 miles per gallon, how many miles could it travel on a full tank?
One half of the employees of Al Karim Co. earn salaries above Rs. 18,000 monthly. One third of the remainder earn salaries between Rs. 15,000 and Rs. 18,000. What part of the staff earns below Rs. 15,000 ?
If a pipe can fill a tank in 2 hours and another pipe can fill the same tank in 40 minutes. How much time in minutes is needed to fill the tank if both the pipes are working together ?