<PRE><B>Question 549935</B>
Mrs. Carter owns a shop specializing in tea. 
She combines 1 lb. Darjeeling with 3 lbs. Earl Grey to get a 4lb mixture of 25% Darjeeling. 
SHe chooses to change the mixture to 50% Darjeeling. How much Darjeeling should she add to bring the mixture to 50%?
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Equation:
Dar + Dar  = Dar
0.25*4 + x = 0.50(4+x)
Multiply thru by 100 to get:
25*4 + 100x = 50*4 + 50x
50x = 25*4
x = 2 lb (amt. of Darjeeling she must add)
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Cheers,
Stan H.
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