Question

SOLUTION: George invested some money at 5% interest. George also invested $219 more than 4 times that amount at 10%. How much is invested at each rate if George receives $922.80 in interest

Answer 1

$1564 was invested at 5%

$6475 was invested at 10%

Explanation:

Let the amount invested at 5% be X

And that invested at 10% be Y.

Interest on X

`I_X=X *5\%=0.05X`

Interest on Y

`I_Y=Y *10\%=0.1Y`

From the question,

`Y=4X+219`

Interest on Y

`I_Y=0.1(4X+219)=0.4IX+21.9`

Also, from the question, both interests add up to $922.80

`I_X + I_Y = 922.8`

`0.05X + 0.4X+21.9 = 922.8`

`0.45X = 922.8- 21.9= 703.8`

`X=(703.8)/(0.45)=1564`

`Y = 4X+219=4*1564+219`

`Y=6256+219=6475`