t=2%
e=10%
t+e=6000
2t+10e=6000*5
2t+10e=30000
divide both sides by 2
t+5e=15000
we have
t+e=6000
t+5e=15000
multiply first equation by -1 and add to second
-t-e=-6000
t+5e=15000 +
0t+4e=9000
4e=9000
divide both sides by 4
e=2250
sub back
t+e=6000
t+2250=6000
minus 2250 from both sides
t=3750
3750ml of the 2% solution
2250ml of the 10% solution