SOLUTION: Joe created a metal containing 40% platinum by combining two other metals. One of these other metals weighed 12 lb. and contained 45% platinum. If the other weighed 3 lb. then what

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Question 1015689: Joe created a metal containing 40% platinum by combining two other metals. One of these other metals weighed 12 lb. and contained 45% platinum. If the other weighed 3 lb. then what percent of it was platinum?
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
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x=percentage of other metal
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(0.45)(12lbs)+x(3lbs)=(0.40)(15lbs)
5.4lbs+3xlbs=6.0lbs . Subtract 5.4 lbs from each side.
3xlbs=0.6lbs . Divide each side by 3 lbs
x=0.2
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ANSWER: The other metal was 20% platinum.
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