Question

a plate moving at a rate of 3 cm/year is moving toward a plate that is 1,500 km away. in how many years will the plates collide?
50,000,000 years
50,000 years
5,000 years
500 years

Explanation:

Step1: Convert distance to cm

Since $1\ \text{km}=100,000\ \text{cm}$, $1500\ \text{km}=1500\times100,000 = 1.5\times10^8\ \text{cm}$

Step2: Calculate time to collision

Time = $\frac{\text{Total Distance}}{\text{Speed}} = \frac{1.5\times10^8\ \text{cm}}{3\ \text{cm/year}} = 5\times10^7\ \text{years} = 50,000,000\ \text{years}$

Answer:

50,000,000 years