00:01
All right, let's define our variables.
00:03
I'm going to say x is the money we invest at 4 % interest, and i'm going to say y is the money we invest at 3 % interest.
00:21
And we know, altogether, we're investing $15 ,000.
00:27
So x plus y has to equal $15 ,000, and we know we want to earn $550 in interest annually.
00:39
So we're going to say money in x times 0 .04 plus money in y times 0 .03 has to give us $550.
00:57
We know that if x plus y is 15 ,000, then x must be 15 ,000 minus y.
01:06
So i'm going to say .04, 0 .04 times 15 ,000 minus y, plus 0 .03 times y equals 550.
01:32
So, 15 ,000 times 0 .04 gives us 600, 600 minus 0 .04 y plus 0 .03, plus 0 .03 y...