{
  "address": "3e62459b4c99fb861413e2e0f5de0915",
  "category": "other",
  "question": "What is the final amount of a $1000 principal invested at 5% annual interest, compounded 12 times per year for 10 years?",
  "answer": "$1,647.01",
  "askedBy": {
    "kind": "guest",
    "display": "method deck",
    "stamped": false,
    "id": null
  },
  "answeredBy": "method",
  "madeAt": "2026-09-30T22:39:30.722Z",
  "validUntil": null,
  "validityClass": "forever",
  "sources": [
    {
      "label": "Principles of Corporate Finance",
      "url": null
    }
  ],
  "supersedes": null,
  "supersededBy": null,
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  "seedSource": null,
  "seedAttribution": null,
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  "publishedAt": null,
  "unpublishedAt": null,
  "voteCount": 0,
  "queuedForSubstrate": false,
  "answerMethod": "method",
  "unsourced": false,
  "source": {
    "kind": "edition_page",
    "value": "Brealey, Myers, Allen, Principles of Corporate Finance, 13th ed., Chapter 3, section 3-1 (Compound Interest)",
    "retrieved_utc": "2026-09-30T19:31:29Z"
  },
  "qsha256": "4f170b962f20b86b3155228713c3f4c22920efe942bec88306a6ebe613313798",
  "runOne": null,
  "cardContractVersion": "card_contract/1",
  "deck_id": "method-deck",
  "deck_title": "Method Deck",
  "method": {
    "name": "Compound interest",
    "version": "1",
    "source_url_or_file": "methods/compound-interest.cjs",
    "sha256_of_method_file": "b3e7f67052e07cf4aec7d6dc868531799f6dad8640cfbd5480c9b18d5b181d16"
  },
  "receipt": {
    "inSubstrate": false,
    "local": true,
    "modelCallsAtMint": 0,
    "tokensAtMint": 0
  },
  "method_deck": {
    "inputs": [
      {
        "name": "principal",
        "type": "number",
        "unit": "currency units",
        "required": true,
        "description": "Starting amount",
        "min": 0
      },
      {
        "name": "annual_rate_percent",
        "type": "number",
        "unit": "%",
        "required": true,
        "description": "Nominal annual rate",
        "min": 0
      },
      {
        "name": "compounds_per_year",
        "type": "integer",
        "required": true,
        "description": "Compounding periods per year",
        "enum": [
          1,
          2,
          4,
          12,
          52,
          365
        ]
      },
      {
        "name": "years",
        "type": "number",
        "unit": "years",
        "required": true,
        "description": "Term",
        "min": 0
      }
    ],
    "outputs": [
      {
        "name": "final_amount",
        "unit": "currency units",
        "description": "Amount after the term"
      },
      {
        "name": "interest_earned",
        "unit": "currency units",
        "description": "Total interest earned over the term"
      }
    ],
    "steps": [
      "Convert the annual rate to a decimal: r = annual_rate_percent / 100.",
      "Periodic rate i = r / compounds_per_year; periods n = compounds_per_year * years.",
      "final_amount = principal * (1 + i) ^ n, rounded to 2 decimals.",
      "interest_earned = final_amount - principal, rounded to 2 decimals."
    ],
    "constants": [],
    "examples": [
      {
        "name": "worked example",
        "inputs": {
          "principal": 1000,
          "annual_rate_percent": 5,
          "compounds_per_year": 12,
          "years": 10
        },
        "expected": {
          "answer": "$1,647.01"
        },
        "check": "hand computation: i = 0.05/12 = 0.0041666..., n = 120, final = 1000*(1.0041666...)^120 = 1647.0094..., rounds to 1647.01"
      },
      {
        "name": "test vector: annual compounding",
        "inputs": {
          "principal": 5000,
          "annual_rate_percent": 4,
          "compounds_per_year": 1,
          "years": 5
        },
        "expected": {
          "answer": "$6,083.26"
        },
        "check": "hand computation: final = 5000*(1.04)^5 = 6083.2603..., rounds to 6083.26"
      }
    ],
    "disclaimer": null,
    "deck_category": "finance"
  },
  "status": "minted",
  "kind": "method",
  "provenanceClass": "own_question",
  "provenance": {
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    "chain": [
      {
        "source": {
          "kind": "edition_page",
          "value": "Brealey, Myers, Allen, Principles of Corporate Finance, 13th ed., Chapter 3, section 3-1 (Compound Interest)",
          "retrieved_utc": "2026-09-30T19:31:29Z"
        },
        "sha256": "a30cefdfb083435a602e42db856ea7701609356e258d28070f0b412cfcd8de80",
        "supersedes": null,
        "added_utc": "2026-09-30T22:39:30.722Z",
        "added_by": "method:Compound interest",
        "why": "the method that computed this answer",
        "check": null,
        "status_label": "pending",
        "signature": null
      }
    ]
  }
}