1. **State the problem:** Car A is moving north at 45 kph. Car B starts 12 minutes (which is \(\frac{12}{60}=0.2\) hours) later at 54 kph. We need to find how long it takes Car B to overtake Car A after Car B starts. 2. **Define variables:** Let \(t\) be the time in hours Car B travels until it catches up with Car A. 3. **Express distances traveled:** Distance Car A traveled before Car B starts: \(d = 45 \times 0.2 = 9\) km Distance Car A travels during time \(t\): \(45t\) Distance Car B travels during time \(t\): \(54t\) 4. **Set up the equation for overtaking:** Car B overtakes Car A when both have traveled the same total distance from the original starting point: $$9 + 45t = 54t$$ 5. **Solve for \(t\):** $$9 = 54t - 45t = 9t$$ $$t = \frac{9}{9} = 1$$ hour 6. **Interpretation:** It takes Car B **1 hour** to overtake Car A after Car B starts moving. **Final answer:** \(\boxed{1\text{ hour}}\)