The rancher sells beef to ruth chris steakhouse for $15.00. ruth chris sells a fillet to a customer for $30.00. what is the total contribution to gdp?

Here is the formula to calculate GDP:
GDP = C + G + I + NX
Where I is the investment that include all form of capital expenditure

Both sales mentioned above could be considered as a form of Capital expenditure, so the total contribution to GRP would be:
$30 + $ 15 = $ 45