A rectangular field will have one side made of a brick wall and the other three sides made of wooden fence. Brick wall costs20dollars per meter and wooden fence costs30 dollars for3 meters. The area of the field is to be150 square meters.

What length should the brick wall be to give the lowest total cost of wall plus fence?

length of the brick wall=

A wise old troll wants to make a small hut. Roofing material costs five dollars per square foot and wall materials cost three dollars per square foot. According to ancient troll customs the floor must be square, but the height is not restricted.

If the troll has only540dollars to spend, what is the biggest volume hut he can build?

Largest volume= ______ cubic feet

A poster is to have a total area of180. There is a margin round the edges of6cm at the top and4cmat the sides and bottom where nothing is printed.What width should the poster be in order to have the largest printed area?T

The poster should have width_______cm