Question 721441
"Louise, Janelle, and Nicole are trying to dunk Neil into a dunk tank. They have to put weights onto a scale and have the total weight be 100 pounds.
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Louise puts on 3 blue weights and 7 red weights and her total weight is only 45 pounds. Janelle puts on 6 blue weights and 4 red weights and her total is only 70 pounds. How many blue and red weights does Nicole need to put on the scale in order to dunk Neil?"
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3b + 7r = 45 lbs.
6b + 4r = 70 lbs.
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Modify the top equation:
6b + 14r = 90
6b + 4r  = 70
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Subtract and solve for "r":
10r = 20
red = 2 lbs (each red weight weighs 2 lbs
Note: 50 red discs would equal 100 lbs.
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Solve for "b":
3b + 7r = 45
3b + 14 = 45
3b = 31
blue = 10 1/3 lbs (each blue weight weighs 10 1/3 lbs)
Note: 10 blue discs would equal more than 100 lbs.
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Note: Many other combinations of red and blue would 
weigh at least 100 lbs.
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Cheers,
Stan h.
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