Question 883311
1.{{{X+Y=3500}}}
.
.
.
{{{0.04X+0.05Y=153}}}
2.{{{4X+5Y=15300}}}
Multiply eq. 1 by -4 and add to eq. 2,
{{{-4X-4Y+4X+5Y=-14000+15300}}}
{{{Y=1300}}}
Then from eq. 1,
{{{X=3500-1300}}}
{{{X=2200}}}