Question 354753
You have a mix of a 6% solution & an 8% solution. 
Where is the 10% solution???
Maybe you meant 10 liters? 
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.08x+.06(10-x)=/.07*10
.08x+.6-.06x=.7
,02x=,7-.6
.02x=.1
x=.1/.02
x=5 ans. for the amount of 8% solutio used.
Proof:
.08*5+.06*5=.07*10
.04+.03=.07
.07=.07
5 liters of 6% if mixed with 5 liters of 8% yields 10 liters of a 7% solution.