Answer:
9.28 × 10⁻⁴ cm/year.
Step-by-step explanation:
Let d(t₀) represent the initial position of Kauai island = 0 km from the hot spot. at time t = 0 million years. Let d(t₁) represent its final position at time t₁ = 5.1 million years later in the North - west direction. d(t₁)=473 km = 4.73 × 10³ cm. The average speed v = total distance/ total time =[d(t₁) - d(t₀)]/t₁₋t₀ = (4.73 × 10³ - 0)/(5.1 × 10⁶ - 0) = 4.73/5.1 × 10³⁻⁶ = 9.275 × 10⁻⁴ cm/year ≅ 9.28 × 10⁻⁴ cm/year