Final answer:
To find the percentage change from the first quantity to the second quantity, use the formula for percentage decrease: (change in value / initial value) * 100%. In this case, the percentage change from 60 km/h to 45 km/h is 25%.
Step-by-step explanation:
To find the percentage change from the first quantity to the second quantity, we need to calculate the percentage decrease. The formula for percentage decrease is:
Percentage decrease = (change in value / initial value) * 100%
In this case, the change in value is 60 km/h - 45 km/h = 15 km/h, and the initial value is 60 km/h. Plugging these values into the formula, we get:
Percentage decrease = (15 km/h / 60 km/h) * 100% = 25%
Therefore, the percentage change from 60 km/h to 45 km/h is 25%.