1. Problem 1: We want to find the water level in Macopo Dam on May 5. 2. The water level decreases to 5% of the previous day’s level each day, so the decay factor is $0.05$. 3. The initial water level on May 1 is $1230$ cubic meters. 4. The water level on day $n$ is given by the formula: $$L_n = 1230 \times 0.05^{n-1}$$ where $n=1$ corresponds to May 1. 5. May 5 corresponds to $n=5$, so the water level is: $$L_5 = 1230 \times 0.05^{4} = 1230 \times (0.05 \times 0.05 \times 0.05 \times 0.05) = 1230 \times 0.00000625 = 0.0076875$$ cubic meters. 6. Problem 2: We want to find how many days until the plant is 150% taller than its initial height. 7. The initial height is 10 cm. 8. 150% taller means height increases by 150% of initial, so the target height is: $$10 + 1.5 \times 10 = 10 + 15 = 25 \text{ cm}$$ 9. The plant grows $0.75$ cm every day. 10. If $d$ is the number of days waited, height after $d$ days is: $$10 + 0.75d = 25$$ 11. Solve for $d$: $$0.75d = 25 - 10 = 15$$ $$d = \frac{15}{0.75} = 20$$ 12. Answer: Justine will have to wait 20 days until the plant is 150% taller. Final answers: - Water level on May 5: approximately $0.0077$ cubic meters. - Days to reach 150% taller: $20$ days.