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April 11th, 2018, 12:02 AM  #1 
Senior Member Joined: Aug 2014 From: India Posts: 183 Thanks: 1  Find the average weight of the total students.
The average weight of 30 students is x kg and the average weight of another 30 students is y kg. The ratio of x and y is 2:3. Find the average weight of the total students. I tried: $\displaystyle \frac {30(X) + 30(Y)}{X+Y}$ $\frac {X}{Y}$= $\displaystyle \frac{2}{3}$ X = $\displaystyle \frac {2Y}{3}$ $\displaystyle \frac {30(\frac {2}{3})Y + 30Y}{\frac {2}{3}Y+Y}$ $\displaystyle 3 \frac{20Y+30Y}{2Y+3Y}$ $\displaystyle 3(10) \frac{5y}{5y}$ = 30 But answer is $\displaystyle \frac {X+Y}{2} $ Last edited by Ganesh Ujwal; April 11th, 2018 at 12:10 AM. 
April 11th, 2018, 12:05 AM  #2 
Senior Member Joined: Oct 2009 Posts: 350 Thanks: 113  
April 11th, 2018, 12:11 AM  #3 
Senior Member Joined: Aug 2014 From: India Posts: 183 Thanks: 1  
April 11th, 2018, 12:14 AM  #4 
Senior Member Joined: Oct 2009 Posts: 350 Thanks: 113 
I'm just pretending to be an expert according to some people, so I'm sure you wouldn't want my help! http://mymathforum.com/feedback/3438...questions.html 
April 11th, 2018, 12:15 AM  #5  
Senior Member Joined: Aug 2014 From: India Posts: 183 Thanks: 1  Quote:
 
April 11th, 2018, 12:16 AM  #6 
Senior Member Joined: Nov 2010 From: Indonesia Posts: 1,867 Thanks: 130 Math Focus: Trigonometry and Logarithm  

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