00:01
$20 ,000.
00:01
Part of it was at 8 % and another part was at 18%.
00:05
At the end of the year, they had $2 ,000 in interest.
00:09
So how much was invested at 8 %? well, let's find out.
00:13
Let's let x be the amount at 8%, which means $20 ,000 minus x is going to be the amount at 18%.
00:21
How does this work with our interest? well, interest is principal times rate times time.
00:26
We're talking about one year, so we just need principal and rate.
00:29
So this would be .08x plus .18, $20 ,000 minus x.
00:37
There's my principal times our rate.
00:39
When we combine those together, we get the $2 ,000.
00:42
Let's go ahead and see what .18 times $2 ,000 is...