00:03
To work our way through the parts of this problem, we're going to use the equation, interest equals principle times rate times time, and the balance equals the principle plus the interest.
00:12
And in this problem, regina is depositing $3 ,500, so that's the principle, and the annual interest rate is 7 .5%, which we convert to a decimal .075.
00:27
Okay, for part a, we want to know how much interest she earns in the first six months.
00:32
So we use interest equals principle times rate times time.
00:36
So interest equals 3 ,500, the principal, times 0 .075 the rate, times one half for the time because six months is half a year.
00:47
We multiply all of those together and we get $131 .25.
00:57
Now for part b, we want to know her balance at the end of the first six months.
01:02
So to get her balance, we add her principal, $3 ,500, to her interest, $1 ,500 .1%.
01:08
$1 .35.
01:10
So she now has $3 ,631 .25.
01:18
Okay, for part c, another six months goes by and she earns interest again at the end of the six months.
01:25
So we want to find out how much interest she earns now.
01:29
So again, to find the interest, we take the interest equals principle times rate times time, but at this point, her principal is $3 ,631 .25...