Explain a "3-fund portfolio" for someone new to investing. Cover:
1. What the three funds typically are (US stocks, international stocks, bonds) and why this mix.
2. Example tickers (e.g., VTI, VXUS, BND or equivalent) and what they represent.
3. How to choose ratios (e.g., 70/20/10 vs 60/30/10) based on age and risk tolerance.
4. Where to hold them (IRA vs taxable) and why allocation might differ by account.
5. One paragraph on rebalancing (what it is, how often, simple method).
Use plain language. Assume I have a long time horizon and am in the US.