
Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion 
 LinkBack  Thread Tools  Display Modes 
October 9th, 2018, 04:09 AM  #1 
Senior Member Joined: Aug 2014 From: India Posts: 343 Thanks: 1  What is the percentage of milk in the resultant mixture?
33.3 litres of a mixture containing 43% milk is mixed with 55.5 lit of one containing 59% milk. What is the percentage of milk in the resultant mixture? Answer is 53%. I can take ratio of 33.3/55.5 i.e 3:5 After that, how to proceed the solution? 
October 9th, 2018, 04:45 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 19,974 Thanks: 1850 
Writing 3:5 as 0.6, and the given percentages as 0.43 and 0.59, you need to find (0.43 Ã— 0.6 + 0.59)/(0.6 + 1), which simplifies to exactly 0.53. Hence the answer is 53%. 
October 9th, 2018, 05:02 AM  #3 
Senior Member Joined: Aug 2014 From: India Posts: 343 Thanks: 1  
October 9th, 2018, 06:05 AM  #4 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,608 Thanks: 954 
......a @ u% ......b @ v%  (a+b) @ w% w = (au + bv) / (a + b) 
October 9th, 2018, 06:29 AM  #5 
Global Moderator Joined: Dec 2006 Posts: 19,974 Thanks: 1850 
An equivalent equation is w = ((a/b)u + v)/(a/b + 1), which is what I used.

October 9th, 2018, 06:34 AM  #6 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,608 Thanks: 954 
Mine is shorter and simpler 
October 9th, 2018, 07:56 AM  #7 
Global Moderator Joined: Dec 2006 Posts: 19,974 Thanks: 1850 
In general, yes. For the posted problem, the evaluation of the formula happens to be easier to do when using the longer formula, because a/b = 0.6, which is rather convenient for mental arithmetic.

October 9th, 2018, 08:33 AM  #8 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,608 Thanks: 954 
Why memorize a 2nd formula in case ratio is an "easy division"?

October 9th, 2018, 09:21 AM  #9 
Global Moderator Joined: Dec 2006 Posts: 19,974 Thanks: 1850 
I didn't suggest memorizing it. I used it because I realized it would be easier.

October 9th, 2018, 09:29 AM  #10 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,608 Thanks: 954 
Not important...just fooling around...


Tags 
milk, mixture, percentage, resultant 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
sector length. and resultant load  Naz Ar  Geometry  6  October 12th, 2018 12:40 PM 
3 phase AC signal resultant vector  MathsLearner123  Geometry  5  May 17th, 2018 06:37 PM 
Resultant Force  mrbronz  Physics  3  September 25th, 2015 07:21 AM 
How to find the resultant force on the object  girlbadatmath  Physics  9  July 17th, 2014 02:24 AM 
find resultant and angle  mt055  Algebra  1  November 3rd, 2009 04:39 PM 