SOLUTION: ricardo needs to have a 20% solution of antifreeze and water in his radiator. if the Radiator of truck contains 8 quarts of Solution of antifreeze and water, with 10% being antifre

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Question 214190: ricardo needs to have a 20% solution of antifreeze and water in his radiator. if the Radiator of truck contains 8 quarts of Solution of antifreeze and water, with 10% being antifreeze, how much antifreeze must be added to create the desired solution
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
This problem assumes that his radiator is big
enough to hold the extra antifreeze he's adding,
just to be aware
Let a = quarts of antifreeze he needs to add
In words:
(original amount of antifreeze + antifreeze to be added)/(final quarts of mixture in radiator) = 20%
--------------------------
Given:
.1%2A8+=+.8 quarts of original atifreeze in radiator
%28.8+%2B+a%29%2F%288+%2B+a%29+=+.2
.8+%2B+a+=+.2%2A%288+%2B+a%29
.8+%2B+a+=+1.6+%2B+.2a
.8a+=+.8
a+=+1
He must add 1 quart of antifreeze (assuming the radiator can hold
8+%2B+1+=+9 quarts)
check answer:
Now he has .8+%2B+1+=+1.8 quarts of antifreeze in radiator
and 9 quarts total mixture
1.8%2F9+=+.2 He has 20% antifreeze
OK