document.write( "Question 143667: I am having a lot of trouble with word problem questions. If someone could help me that would be great. If you could show your work so that I can understand how you got the answer would be apprectiated. Thanks so much!\r
\n" ); document.write( "\n" ); document.write( "*In a certain medical test designed to measure carbohydrate tolerance, and adult drinks 7 ounces of a 30% glucose solution. When the test is administered to a child, the glucose concentration must be decreased to 20%. How much 30% glucose solution and how much water should be used to prepare 7 ounces of 20% glucose solution?\r
\n" ); document.write( "\n" ); document.write( "*Theophylline, is prepared from an elixir with a drug concentration of 5 mg/ml and a cherry-flavored syrup that is to be added to hide the taste of the drug. How much of each must be used tp prepare 100 mililiters of solution with a drug concentratio of 2 mg/ml?\r
\n" ); document.write( "\n" ); document.write( "*Two children who are 224 meters apart, start walking toward each other at the same instant at rates of 1.5m/sec and 2 m/sec, respectively.
\n" ); document.write( "(a) When will they meet?
\n" ); document.write( "(b) How far will each have walked?\r
\n" ); document.write( "\n" ); document.write( "*A wafer cone is to hold 8 in^3 of ice cream when filled to the bottom. The diameter of the cone is 2 inches, and the top of the ice cream has the shape of a hemisphere. Find the height (h) of the cone.\r
\n" ); document.write( "\n" ); document.write( "*A runner starts at the beginning of a runners' path and runs at a constant rate of 6 mi/hr. Five minutes later a second runner begins at the same point, running at a rate of 8 mi/hr and following the same course. How long will it take the second runner to reach the first?
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Algebra.Com's Answer #104554 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
In a certain medical test designed to measure carbohydrate tolerance, and adult drinks 7 ounces of a 30% glucose solution. When the test is administered to a child, the glucose concentration must be decreased to 20%. How much 30% glucose solution and how much water should be used to prepare 7 ounces of 20% glucose solution?
\n" ); document.write( ":
\n" ); document.write( "Let x = amt of 30% glucose solution
\n" ); document.write( "We want the resulting total to be 7 oz, therefore
\n" ); document.write( "(7-x) = amt of water required (water is a 0% solution)
\n" ); document.write( ":
\n" ); document.write( "A percent glucose equation.
\n" ); document.write( ":
\n" ); document.write( "The amt of glucose remains the same, (the percent changes by adding water)
\n" ); document.write( ":
\n" ); document.write( ".30x = .20(7)
\n" ); document.write( ".3x = 1.4
\n" ); document.write( "x = \"1.4%2F.3\"
\n" ); document.write( "x = 4\"2%2F3\" oz of 30% solution
\n" ); document.write( "then
\n" ); document.write( "7 - 4\"2%2F3\" = 2\"1%2F3\" oz of water
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "*Theophylline, is prepared from an elixir with a drug concentration of 5 mg/ml and a cherry-flavored syrup that is to be added to hide the taste of the drug. How much of each must be used to prepare 100 milliliters of solution with a drug concentration of 2 mg/ml?
\n" ); document.write( ":
\n" ); document.write( "Let x = amt of 5 mg elixir required
\n" ); document.write( "then
\n" ); document.write( "(100-x) = amt of syrup required
\n" ); document.write( ":
\n" ); document.write( "5x = 2(100)
\n" ); document.write( "5x = 200
\n" ); document.write( "x = \"200%2F5\"
\n" ); document.write( "x = 40 ml of elixir
\n" ); document.write( "then
\n" ); document.write( "100-40 = 60 ml of syrup
\n" ); document.write( ":
\n" ); document.write( ";
\n" ); document.write( "*Two children who are 224 meters apart, start walking toward each other at the same instant at rates of 1.5m/sec and 2 m/sec, respectively.
\n" ); document.write( ":
\n" ); document.write( "The total distance of both will equal 224 meters. Write a distance equation:
\n" ); document.write( "Dist = speed * time
\n" ); document.write( ":
\n" ); document.write( "(a) When will they meet?
\n" ); document.write( "Let t = time (in sec) when they meet:
\n" ); document.write( ";
\n" ); document.write( "child 1 dist + child 2 dist = 224 meters
\n" ); document.write( "1.5t + 2t = 224
\n" ); document.write( "3.5t = 224
\n" ); document.write( "t = \"224%2F3.5\"
\n" ); document.write( "t = 64 seconds
\n" ); document.write( ":
\n" ); document.write( "(b) How far will each have walked?
\n" ); document.write( "now we know t
\n" ); document.write( "1.5*64 = 96 meters (child 1)
\n" ); document.write( "2.0*64 = 128 meters (child 2)
\n" ); document.write( "--------------
\n" ); document.write( "total = 224, confirms our solution
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "*A wafer cone is to hold 8 in^3 of ice cream when filled to the bottom. The diameter of the cone is 2 inches, and the top of the ice cream has the shape of a hemisphere. Find the height (h) of the cone.
\n" ); document.write( ":
\n" ); document.write( "The vol of a cone + the vol of half sphere = 8 cu in
\n" ); document.write( "r=1 in (half the diameter
\n" ); document.write( "\"%281%2F3%29%2Api%2Ar%5E2%2Ah\" + \"%281%2F2%29%2Api%2Ar%5E2\" = 8
\n" ); document.write( "using the given values for r
\n" ); document.write( "\"%281%2F3%29%2Api%2A1%5E2%2Ah\" + \"%281%2F2%29%2Api%2A1%5E2\" = 8
\n" ); document.write( ":
\n" ); document.write( "\"%281%2F3%29%2Api%2A1%2Ah\" + \"%281%2F2%29%2Api%2A1\" = 8
\n" ); document.write( "Use a calc
\n" ); document.write( "1.0472h + 1.5708 = 8
\n" ); document.write( ":
\n" ); document.write( "1.0472h = 8 - 1.5708
\n" ); document.write( ":
\n" ); document.write( "1.0472h = 6.4292
\n" ); document.write( "h = \"6.4292%2F1.0472\"
\n" ); document.write( "h = 6.14 inches the height of the cone part only, the part including hemisphere would be an inch higher, 7.14\"
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "*A runner starts at the beginning of a runners' path and runs at a constant rate of 6 mi/hr. Five minutes later a second runner begins at the same point, running at a rate of 8 mi/hr and following the same course. How long will it take the second runner to reach the first?
\n" ); document.write( ";
\n" ); document.write( "We know that when the 2nd runner catches up with the 1st, they will have run the same distance.
\n" ); document.write( ":
\n" ); document.write( "Change 5 min to hrs: 5/60 = 1/12
\n" ); document.write( ":
\n" ); document.write( "Let t = run time of the 2nd runner
\n" ); document.write( "then
\n" ); document.write( "(t+\"1%2F12\") = run time of the 1st runner
\n" ); document.write( ":
\n" ); document.write( "Write a dist equation: Dist = speed * time
\n" ); document.write( ":
\n" ); document.write( "Fast runner dist = slow runner dist
\n" ); document.write( "8t = 6(t+\"1%2F12\")
\n" ); document.write( "8t = 6t + \"1%2F2\"
\n" ); document.write( "8t - 6t - \"1%2F2\"
\n" ); document.write( "2t = \"1%2F2\"
\n" ); document.write( "t = \"1%2F2\" * \"1%2F2\"
\n" ); document.write( "t = \"1%2F4\" hr or we can say 15 min for the 2nd runner to catch the 1st
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "We can check solution by finding the distance traveled by each runner (should be equal)
\n" ); document.write( "1st runners time = 20 min, 2nd runner 15 min
\n" ); document.write( "6 * (20/60) = 2 mi
\n" ); document.write( "8 * (15/60) = 2 mi
\n" ); document.write( ":
\n" ); document.write( "Hope you can follow all this, you can ask me about it until 9:15 central daylight or tomorrow. ankor@dixie-net.com\r
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