Please help, I've spent 6 hours on this?

Question

I know the answer to this problem (it is in the back of my book), but I cannot figure out the equation.

In an Individual Retirement Account valued at $53,900, a couple has 500 shares of stock, some in Big Bank Corporation and some in Safe Savngs and Loan. If Big Bank sells for $115 per share and Safe Savings sells for $97 per share, how many shares of each does the couple own?

The first person that can explain how to get the algebraic expression(and is right) will get the points!

Answer 1

bigbank = b
safe save = s
b+s=500 --- (1)
115b+97s=53900 --- (2)
b=500-s --(3)
(3)->(2)
115(500-s) + 97s = 53900
57500-53900 = 18s
s=200
b=500-200
b=300
viola
s=200
b=300

do i get da pnts? thx..

Answer 2

Let x = the number of shares in Big Bank Corp and let y = number of shares in Safe Savings

We know that the total number of shares is equal to 500 and that the first equation would be:

x + y = 500

We also know that the total value of the account is $53,900 and from that the next equation follows:

$115x + $97y = $53,900

Now solve the second equation for either x or y and substitute that answer into the first equation

x = 500 - y

115 (500 - y) + 97y = 53900
57500 - 115y +97y = 53900
-18y = -3600
y = 200

substitiuting for y into the first equation:

x + 200 = 500
x = -200+500 = 300

Answer 3

There are two equations:
x + y = 500
115x + 97y = 53,900

Solve the first equation for x such that:
x = 500 - y

Substitute for x in the second equation, such that:
115(500 - y) + 97y = 53,900

Simplify that equation:
57,500 - 115y + 97y = 53,900

Simplify again:
57,500 - 18y = 53,900

Subtract 53,900 from both sides of the equation:
3,600 - 18y = 0

Add 18y to both sides of the equation:
3600 = 18y

Divide both side by 18:
200 = y

Substitute for y in the first equation:
x + 200 = 500

Subtract 200 from both sides:
x = 300

Answer 4

A couple cannot own an Individual Retirement Account.

Answer 5

Not enough to please the IRS.