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Ratios
Math
Middle School Math

 Name _____________________________ Date ___________________
Ratios
Complete.
 1 Christopher had three out of five of the 20 items required to start the school year. What fraction of the number of items was he lacking?
 2 At ski slope A, the change in elevation from the top of the run to the finish is -1,100 meters. At ski slope B the change is -1,600 meters. If slope A is 700 meters long and slope B is 1,600 meters long what is the elevation-drop-per-meter ratio between slope A and B?

Complete.
 3 If the ratio of saturated to unsaturated fatty acids in a cell membrane is 9 to 1, and there are a total of 69 billion fatty acid molecules, how many of them are saturated?
 4 If four out of every seven individuals in a population of armadillos carry a gene for a defective enzyme, how many individuals carry the normal gene in a population of 843 armadillos?

 Key #2
Complete.
 5 Soils around the world vary in their organic matter content. Organic matter comes from living things or things that used to be alive. For example, in comparing a soil from Nebraska to one from Arizona, it would not be unusual for the Nebraska soil to have a greater amount of organic matter by a factor of 5 to 1. If you had two such samples and the sample from Arizona contained 8 g of organic matter, how many grams of organic matter would there be in Nebraska soil of equal mass? Round your answer to the nearest hundredth.
 6 Based on what has been found so far, the ratio of fossil floopasaurs to fossil bloopia in Africa is 5 to 1. If this ratio is later discovered to have an error of 30% (too high) for floopasaurs, what would the corrected ratio be?

Complete.
 7 Rachel dropped rock 1 (mass = 1.8 kg) from a height of 13 meters. She then dropped rock 2 (mass = 2.7 kg) from the same height. What was the ratio of kinetic energies of the rocks (KErock1/KErock2) when they hit the ground? (note: the acceleration of gravity is 9.81 m/s2.)
 8 Space ship Z is traveling at 178,000 miles per second. Spaceship Q is traveling at 173,000 miles per second. What is the ratio of speeds (Z/Q) of the two spaceships? Express your answer in terms of the maximum speed of light, which is 186,000 miles per second.

Complete.
 9 For every two million pounds of fertilizer manufactured at Bigearth, Inc., about 480 pounds are ruined by being accidentally left out in the rain. Last month, 300 pounds were ruined. Based on this information, estimate how many pounds of fertilizer were manufactured last month. Round your answer to the nearest whole number if needed.
 10 In a mixture of CaCO3 and CaSO4 the ratio of CaCO3 to CaSO4 molecules is 7 to 5. If there are 35 billion molecules of CaSO4, how many total molecules are in the mixture?

 Key #2
Complete.
 11 In the local coed softball league, the male to female ratio is 6:5. If there are 138 players in the league, how many are female?
 12 Nicholas has a record of winning 2 boxing matches for every 3 he loses. If he had 48 matches during the last year, how many did he win?

Sample
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