Question 762944
Amy needs to make 10L of 42% sulphuric acid solution. In the supply room , she finds bottles of 30% sulphuric acid solution and 60% sulphuric acid solution. What volume of each solution should she mix in order to make the 42% solution ? 

So far I have the two equations : 
x+y= 10 
0.3x+0.6y=0.42 ******
The 2nd equation is 0.3x + 0.6y = 0.42*10
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You can use:
x + y = 10
30x + 60y = 42*10