Question 317349
Let A be the amount in the COD, B in the mutual fund.
1.{{{A+B=1000}}}
.
.
{{{0.04A+0.08B=68}}}
2.{{{4A+8B=6800}}}
Multiply eq. 1 by -4 and add to eq. 2,
{{{-4A-4B+4A+8B=-4000+6800}}}
{{{4B=2800}}}
{{{highlight(B=700)}}}
Then from eq. 1,
{{{A+700=1000}}}
{{{highlight(A=300)}}}