A tin can has a circular base and a volume of80cm^3. Express the diameter of the base of the can in terms of the height of the can. Use h for the height of the can.

Diameter=

There are two positive numbers. Four times the small number plus 3 times the big number is 56. Two times the small number plus the big number is 22. What is 10 times the big number minus 6 times the small number;

Answer =

A car travels 330 miles in 6 hours. It travels at 50 mph for the first two hours and travels the last 180 miles at 60 miles per hour. It travels at constant speed for the remaining time.

(a) How long did it take to travel the first 150 miles?

b) Where was the car after 3 hours?

The population of a country is growing exponentially. The population in millions was 80 in 1970 and 90 in 1980.

(a) What is the population t years after 1970?

(b) How long does it take the population to double?

(c) When will the population be 400 million?

Plane A leaves New York at noon (EST) traveling to Los Angeles along a route which is 2500 miles. Plane A travels at 300 mph for the first and last half hour of flight, and at 600 mph for the rest of the flight. Plane B takes off from Los Angeles 1 hour after plane A takes off. Plane B flies along the same route. Plane B flies at 250 mph for the first half hour and last half hour and flies at 500 mph for the rest of the flight. The flight route goes over Salt Lake City, which is 700 miles long the route from Los Angeles.

How far from Salt Lake city is the point where the two planes pass each other?

A river flows at a speed of 5 mph towards sea. A woman in a canoe can paddle through water at a speed of 6 mph. She wishes to paddle for a total time of 2 hours, first upstream (away from the sea) then turning round and paddling back to her starting point.

How long should she paddle upstream?

A plane has an averageair speed(this is the speed the plane moves through air) of 750 mph. The plane flies a route of 5000 miles from Los Angeles to London. The average speed of the wind along this route is 60 mph blowing east from Los Angeles towards London.

How much longer does it take the plane to fly from London to Los Angeles than the reverse direction?

A building has a hemispherical roof. The roof is to be painted with a layer of paint one millimeter thick. The radius of the hemisphere is 20 meters.How many liters of paint are needed?

A water tank has a circular base of radius 3 meters.

(a) If water is entering the tank at the rate of 50 liters per minute, how quickly is the level of the water rising?

____ meter per minute

(b) If the tank is 5 meters high, how long until the tank if full?

____minutes

The number of items sold at a price of x dollars per item is 2000-300x. It costs 3 dollars to make the item.

What price should be charged to make the most profit?

___dollars