SOLUTION: James made two glasses of chocolate milk. Glass A had 5% chocolate and Glass B had 10% chocolate. How many ounces of each do you need for a 50 ounce glass of 8% chocolate?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: James made two glasses of chocolate milk. Glass A had 5% chocolate and Glass B had 10% chocolate. How many ounces of each do you need for a 50 ounce glass of 8% chocolate?       Log On


   



Question 1096627: James made two glasses of chocolate milk. Glass A had 5% chocolate and Glass B had 10% chocolate. How many ounces of each do you need for a 50 ounce glass of 8% chocolate?

Found 2 solutions by josmiceli, greenestamps:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = ounces of 5% chocolate milk needed
Let +b+ = ounces of 10% chocolate milk needed
----------------------------------------------
(1) +a+%2B+b+=+10+
(2) +%28+.05a+%2B+.1b+%29+%2F+10+=+.08+
---------------------------------
(2) +.05a+%2B+.1b+=+.8+
(2) +5a+%2B+10b+=+80+
(2) +a+%2B+2b+=+16+
Subtract (1) from (2)
(2) +a+%2B+2b+=+16+
(1) +-a+-+b+=+-10+
-----------------------
+b+=+6+
and
(1) +a+%2B+6+=+10+
(1) +a+=+4+
---------------------
4 ounces of 5% chocolate milk are needed
6 ounces of 10% chocolate milk are needed
-----------------------------------------
check:
(2) +%28+.05a+%2B+.1b+%29+%2F+10+=+.08+
(2) +%28+.05%2A4+%2B+.1%2A6+%29+%2F+10+=+.08+
(2) +%28+.2+%2B+.6+%29+%2F+10+=+.08+
(2) +.8+=+.8+
OK

Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!

The algebraic solution shown by tutor josmiceli is fine. But here is a much fast method for finding the answer.

Compare the percentages of the two ingredients (5% and 10%) to the percentage of the mixture (8%):

10-8=2 ; 8-5+=+3

Those two differences , 2 and 3, mean the two ingredients must be mixed in the ratio 2:3. So to get 50 ounces of mixture, you need 20 ounces of one and 30 ounces of the other.

And since 8% is closer to 10% than it is to 5%, you need more of the 10% ingredient.

So 30 ounces of the 10% chocolate and 20 ounces of the 5% chocolate.