At the end of 2021 there were 27,000 rhinos living in the wild.
The number of rhinos is expected to decrease exponentially by 3% each year.
Work out the number of rhinos expected to be living in the wild 4 years later, at the end of 2025.
Give your answer correct to the nearest whole number.
▶️ Answer/Explanation
Ans: 23,903
Annual decrease factor = 1 – 0.03 = 0.97
Number after 4 years = 27,000 × (0.97)^4
Calculate: 27,000 × 0.88529281 ≈ 23,902.9059
Round to nearest whole number: 23,903
At the start of an experiment there are 40,000 bacteria.
The number of bacteria increases at a rate of 15% per hour.
Calculate the number of bacteria after 3 hours.
▶️ Answer/Explanation
Ans: 60,835
Use compound growth formula: 40,000 × (1.15)³
First hour: 40,000 × 1.15 = 46,000
Second hour: 46,000 × 1.15 = 52,900
Third hour: 52,900 × 1.15 = 60,835