00:02
Okay, so b is going to be our brother's age now, and s is going to be the sister's age now.
00:18
And so right now, a brother is five years older than his sister.
00:23
So sister's age plus five is the brother's age.
00:28
And four years ago, the ratio of their ages was four to three.
00:40
So if we want the ratio of 4 to 3, we would want it to be equal.
00:46
So our brother's age, but this was 4 years ago.
00:50
So minus 4 and sisters age minus 4.
00:54
So i'm going to do some cross multiplication.
01:03
And so now we're going to distribute.
01:10
And now i'm going to go ahead and plug s plus 5 in for brother's age...