R16 set up, solve and interpret the answers in growth and decay problems, including... Quiz: Pearson Edexcel Maths, Unit 3

The 20 questions

1. The compound interest formula for amount A, principal P, rate r% and n years is:

   • A = P + rⁿ
   • A = P(1 + r/100)ⁿ
   • A = P(1 − r/100)ⁿ
   • A = P(1 + rn/100)

2. The multiplier for a 6% increase is:

   • 6
   • 0.06
   • 0.94
   • 1.06

3. The multiplier for a 15% decrease is:

   • 1.15
   • 0.15
   • 0.85
   • 0.015

4. What amount is simple interest always calculated on?

   • Interest earned so far
   • Previous year balance
   • Total accumulated amount
   • Original principal only

5. In an iterative process, what value is used for each new step?

   • previous output
   • initial value only
   • final limit
   • random number

6. What happens to a quantity undergoing exponential decay over equal time intervals?

   • Decreases by same amount
   • Decreases by same percentage
   • Stays completely constant
   • Increases by same percentage

7. The overall multiplier for two consecutive 10% increases is:

   • 1.2
   • 1.1
   • 1.21
   • 0.81

8. In the growth formula A = P(1 + r/100)^n, what does n represent?

   • Total final amount
   • Original principal amount
   • Annual percentage rate
   • Number of time periods

9. £800 is invested at 4% per year compound interest for 3 years. What is the value at the end?

   • £928.00
   • £896.00
   • £899.89
   • £1000.00

10. A population of 50 000 falls by 5% each year for 2 years. What is the population?

    • 47 500
    • 45 125
    • 40 000
    • 45 000

11. A car worth £12 000 depreciates by 12% each year. What is its value after 3 years?

    • £6360.00
    • £7920.00
    • £8177.66
    • £8640.00

12. A colony of 500 bacteria doubles every 3 hours. How many are there after 12 hours?

    • 4000
    • 2000
    • 1000
    • 8000

13. What is the value of £2000 at 2.5% compound interest after 2 years?

    • £2100.00
    • £2050.00
    • £2101.25
    • £2110.00

14. An iteration uses xₙ₊₁ = 0.5xₙ + 4 with x₀ = 0. What is x₂?

    • 6
    • 4
    • 2
    • 8

15. A value grows from 200 to 242 in one year. What is the percentage increase?

    • 2.1%
    • 17.4%
    • 21%
    • 42%

16. A value multiplies by 0.7 each year. After how many full years is it first below 30% of its starting value?

    • 4
    • 2
    • 3
    • 5

17. After 2 years of 5% annual growth, a value is £861. What was the original value?

    • £765.00
    • £800.00
    • £819.00
    • £780.95

18. How many full years does £500 need at 8% compound interest to exceed £700?

    • 3
    • 4
    • 5
    • 6

19. A ball bounces back to 60% of its previous height. After 3 bounces from a height of 2 m, what is the height?

    • 0.36 m
    • 1.2 m
    • 0.6 m
    • 0.432 m

20. In the depreciation model V = 20000 × 0.85^t, what does 0.85 represent?

    • Number of years elapsed
    • Total value lost
    • Annual depreciation amount
    • Remaining value multiplier

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