Final answer:
John's velocity while riding his bicycle to his grandmother's house, which is a distance of 4 km in 45 minutes, was 5.33 km/hr.
Step-by-step explanation:
John rode his bicycle to his grandmother's house, which is 4 km away, in 45 minutes. To calculate his velocity in km/hr, we need to convert 45 minutes to hours and then divide the distance by the time taken. First, we convert 45 minutes to hours by dividing it by 60 (45 minutes / 60 minutes/hour = 0.75 hours). Then we calculate his velocity as follows: Velocity = Distance / Time = 4 km / 0.75 hours = 5.33 km/hr. Therefore, John's velocity was 5.33 km/hr. This means that John covered the distance at an average speed of 5.33 kilometers per hour during his bicycle ride. The conversion from minutes to hours allows for a consistent unit of time, facilitating the velocity calculation and providing a measure of John's speed over the entire journey.