An alloy is composed of nickel, zinc, and copper in a ration of 7: 2: 9. how many kilograms of each metal are needed to make 3.6kg of this alloy?

Gregory draws a scale drawing of his room. the scale that he uses is 1 cm : 4 ft. on his drawing, the room is 3 centimeters long. which equation can be used to find the actual length of gregory's room?

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

How can you tell when x and y are not directly proportional?