Atomic Mass Problem Solving Question

Hi, I am stuck on this homework question and I would like to know how I would go about solving it. Thanks!
Naturally occurring silicon has an atomic mass of 28.086 and consists of three isotopes. The major isotope is 28Si, natural abundance 92.23%, relative atomic mass 27.97693. The next most abundant isotope is 29Si, relative atomic mass 28.97649. The third isotope is 30Si whose natural abundance is in the ratio of 0.6592 to that of 29Si. Find the relative atomic mass of 30Si.

So we know there are 3 isotopes of Silicon, 28, 29, and 30.

Let's solve for the abundance of Si-30 first

The percents will add up to 100

92.23(Si-28) Si-29 Si-30 = 100

92.23 Si-29 Si-30 = 100

We know the relationship between Si-30 to Si-29 is .6592 to 1

If we use x for the percent value of Si-29, Si-30 would be .6592x

Now let's substitute these variables into the equation

92.23 x .6592x = 100

1.6592x = 7.77

x = 4.682979 percent abundance of Si-29

Percent abundance of Si-30 would be .6592x so... 3.08702 percent

We know that percents of each mass will add up to the atomic mass, 28.086, so let's say that the percents times each mass is

.9223(27.97693) .04682979(28.97649) .0308702(y) = 28.086

Y is the relative atomic mass of Si-30, which we do not know but can solve for now that we have the abundance off all isotopes and the atomic masses of most.

If you do some math here you would get

.0308702(y) = .92591452

y = 29.99379725 relative atomic mass of Si-30

Or roughly 29.994 amu