SOLUTION: Eighteen-carat gold contains 18 parts by mass of gold to 6 parts of other metals. Fourteen-carat gold contains 14 parts gold to 10 parts of other metals. How amny kilograms of eigh

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Question 163229: Eighteen-carat gold contains 18 parts by mass of gold to 6 parts of other metals. Fourteen-carat gold contains 14 parts gold to 10 parts of other metals. How amny kilograms of eighteen-carat gold should be mixed with fourteen-carat gold to obtain 60 kg of an alloy containing 17 parts gold and 7 parts of other metals?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Eighteen-carat gold contains 18 parts by mass of gold to 6 parts of other metals.
Fourteen-carat gold contains 14 parts gold to 10 parts of other metals.
:
How many kilograms of eighteen-carat gold should be mixed with fourteen-carat
gold to obtain 60 kg of an alloy containing 17 parts gold and 7 parts of other metals?
:
Let x = no. of kilograms of 18ct alloy required:
Then
(60-x) = no. of kilograms of 14ct alloy required
:
18%2F24x + 14%2F24(60-x) = 17%2F24(60)
Multiply equation by 24 and you have:
18x + 14(60-x) = 17(60)
;
18x + 840 - 14x = 1020
:
18x - 14x = 1020 - 840
:
4x = 180
x = 180%2F4
x = 45 kilo of 18ct alloy required
:
60-45 = 15 kilo of 14ct
:
Check solution in original equation
18%2F24(45) + 14%2F24(15) = 17%2F24(60)
:
810%2F24 + 210%2F24 = 1020%2F24