Question 82580

Let x=amount invested at 8%

Then $22000-x=amount invested at 7%

Interest(I)=Principal(P) times Rate(R) times time(T) or I=PRT 

Interest on amount invested at 8%= 0.08x
Interest on amount invested at 7%= 0.07($22000-x)

Now we are told that the actual interest at the end of the year is $1710.  So:

0.08x+0.07($22000-x)=$1710  get rid of parens

0.08x+$1540-0.07x=$1710  subtract $1540 from both sides

0.08x+$1540-$1540-0.07x=$1710-$1540  collect like terms


0.01x=$170  divide both sides by 0.01

x=$17000-------------------------amount invested at 8%

$22000-x=$22000-$17000=$5000 -----------amount invested at 7%

CK

$5000(0.07)+$17000(0.08)=$1710

$350+$1360=$1710

$1710=$1710

Hope this helps----ptaylor