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 July 5th, 2018, 12:14 AM #1 Senior Member   Joined: Aug 2014 From: India Posts: 310 Thanks: 1 Why 4:7 is not the answer? The contents of two vessels containing water and milk in the ratio 3:5 and 7:8 are mixed in the ratio 4:7. What would be the ratio of water and milk in the final mixture? Please don't post the final answer. My doubt is: Why 4:7 is not considered as ratio of water and milk in the final mixture?
 July 5th, 2018, 02:07 AM #2 Senior Member   Joined: Apr 2014 From: UK Posts: 883 Thanks: 323 Why would you consider it without applying any maths to work it out?
July 5th, 2018, 02:23 AM   #3
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That's not the way you should reply:

Quote:
 Originally Posted by weirddave Why would you consider it without applying any maths to work it out?

when you take four parts of solution 1 (3:5) and seven parts of solution 2 (7: 8 ) , and you then combine the two solution

Then I will understand the question. Hope this helps!

July 5th, 2018, 04:57 AM   #4
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Quote:
 Originally Posted by Ganesh Ujwal That's not the way you should reply....
Aye, aye, Sir...

Hobo at soup kitchen:
"I want my soup lukewarm, in a blue bowl..."

 July 5th, 2018, 05:14 AM #5 Senior Member   Joined: Oct 2009 Posts: 456 Thanks: 149 When you take four parts of solution 1 (3:5) and seven parts of solution 2 (7: 8 ) , and you then combine the two solution
 July 5th, 2018, 07:21 AM #6 Senior Member   Joined: Apr 2014 From: UK Posts: 883 Thanks: 323 Ganesh, I was responding to your doubt, not the math question posed (because you did not want an answer to that). The point I was trying to make was that I completely fail to understand why you would consider that as a possible solution without showing any reason why it might possibly be true. Thanks from topsquark
July 5th, 2018, 07:23 AM   #7
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Quote:
 Originally Posted by Ganesh Ujwal The contents of two vessels containing water and milk in the ratio 3:5 and 7:8 are mixed in the ratio 4:7. What would be the ratio of water and milk in the final mixture? Please don't post the final answer. My doubt is: Why 4:7 is not considered as ratio of water and milk in the final mixture?
4:7 is the ratio of the first mixture to the second. Because they did not have the same ratios of water and milk, that will NOT be the ratio of water and milk in the mixture.

 July 5th, 2018, 09:16 AM #8 Global Moderator   Joined: Dec 2006 Posts: 19,515 Thanks: 1745 Consider a simpler problem. A mixture of 3 pints water and 5 pints milk is added to an equal volume (8 pints) of water. What is the ratio of water to milk that results? Clearly, the answer isn't 1:1. Instead, the resulting mixture has 11 pints water to 5 pints milk.
 July 5th, 2018, 11:30 AM #9 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,115 Thanks: 913 The contents of 2 vessels containing water and milk in ratio 3:5 and 7:8 ... a=3, b=5 c=7, d=8 ....are mixed in the ratio 4:7. u=4, v=7 What would be the ratio of water and milk in the final mixture? r = ratio General case formula for 2 vessels: r = [u*a / (a+b) + v*c / (c+d)] / (u+v) = ? EDIT: answer removed... Last edited by Denis; July 5th, 2018 at 12:03 PM.
 July 5th, 2018, 11:50 AM #10 Global Moderator   Joined: Dec 2006 Posts: 19,515 Thanks: 1745 That comes far too close to posting the final answer.

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