Question 1058599
x at 0.075
10,000-x at 0.085 
They add to 820
.075x+0.085(10,000-x)=820
.075x+850-0.085x=820
-0.01x=-30
multiply both sides by -100
x=$3000@0.075=$225
10,000-x=$7000@0.085=$595
They add to $820.