← Back to Test

Problem 5 - Entrance Test

Algerian oil production declines exponentially: P(t)=120e^(–0.03t) million tonnes per year. In how many years will production drop below 50 million tonnes?

Correct: B

Solve 120e^(–0.03t)=50 → t=–ln(5⁄12)⁄0.03≈29.2 years.