00:01
In this problem, we're told that at a wildlife refuge, the ratio of deer to rabbits is 4 to 9, and we also know that there's 40 more rabbits than deer.
00:09
So what we're trying to do is figure out how many rabbits and deer there are.
00:12
Well, in this case, when we don't know something in math, we can call it a variable.
00:16
So why don't we let d represent the number of deer, and r represent the number of rabbits.
00:22
So because we know the ratio of them is 4 to 9, that means if i have 4 deer compared to 9 rabbits, that would be equal to d divided by r.
00:32
So now we have one equation.
00:34
Now we're also told that there are 40 more rabbits than deer.
00:38
So there's more rabbits than deer, meaning if i want to find the number of rabbits, i have to take the deer and add 40 to it.
00:45
So now we have a system of equations.
00:47
We have two variables and two unknowns.
00:49
I'm going to solve this by substitution.
00:51
So right now i can substitute d plus 40 in place of r in that first equation.
00:56
So we're going to have four ninths equal to d divided by d plus 40.
01:01
So now we have a proportion so we can cross multiply...