Question 908963
We don't know the total invested.
We know the difference in the two accounts.
We know that the interest for the two accounts is $640
0.03*x+0.05*y=640
We know that the account at 3% has $8000 more.
x=8000+y
We substitute for x
0.03*(8000+y)+0.05*y=640
We multiply out
240+0.03y+0.05*y=640
We combine like terms.
0.08*y=400
Isolate y
y=$5000 at 5%
x=8000+y
Calculate x
x=$13000 at 3%
Now,we know the total invested is: 18000
Total invested $13000+$5000=$18000
We check
0.03*13000+0.05*5000=640
390+250=640
640=640
Since this statement is TRUE and neither x nor y is negative all is well.