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Growth on top of growth, and why rates multiply instead of adding.

Pen and paper is fine · no calculator needed why?

Learn first (about 3 minutes)

Opens at level 20.

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Builds on: Money Basics (not open yet) · Percentages in Business (not open yet)

skills · practice stats

From rounds of this course only: box, review and trial answers are left out. Once a skill has 40 tries, it compares your first 20 tries with your last 20.

• Grow for two years par 15 s not tried yet

  worked example

  You invest $9,700. Assume it grows 5% a year, compounding each year. What is it worth after two years?

  Answer: $10,694.25

  1. Year 1: $9,700 × 1.05 = $10,185.
  2. Year 2: $10,185 × 1.05 = $10,694.25.

• Grow for three years par 21 s not tried yet

  worked example

  You invest $20,000. Assume it grows 10% a year, compounding each year. What is it worth after three years?

  Answer: $26,620.00

  1. Multiply by 1.1 three times: $20,000 → $22,000 → $24,200 → $26,620.

• Monthly compounding par 19 s not tried yet

  worked example

  Assume an account adds 0.5% interest at the end of each month. Starting with $10,000, what is the balance after 2 months?

  Answer: $10,100.25

  1. Month 1: $10,000 + $50 = $10,050.
  2. Month 2: $10,050 + $50.25 (0.5% of $10,050) = $10,100.25.

• Total growth over two years par 15 s not tried yet

  worked example

  Assume revenue grows 5% one year and 25% the next. What is the total percentage change over the two years? (Use a minus sign for a decrease.)

  Answer: 31.25%

  1. Multiply the growth factors: 1.05 × 1.25 = 1.3125.
  2. So the total change is 31.25%.

rest ladder

Win 3 of your last 4 rounds and the course rests. A win is 90% right, within 2× the round's par. Pass the review when it comes back and the next rest is longer.

1. 1 day
2. 3 days
3. 7 days
4. 14 days
5. 30 days
6. 60 days
7. mastered · every 90 days

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