Question

larry invested part of his 10,000 advance @ 7% annual simple interest and the rest @ 4% annual simple interest . If his total yearly interest for both accounts is 430, find the amount he invested at each rate.

7% = ?
4%= ?

Answer 1

Let x = the amount at 7% Let y= the amount at 4%

So x+y=$10,000

and .07x + .04y= $430

Rearange equation one and substitute into equation 2

x=$10,000-y

.07(10,000-y) + .04y = 430

y= $9,000

Substitute into the equation one. So x= $10,000- $9,000

x= $1,000

So $1,000 was invested at 7% and $9,000 was invested at 4%