A car covers a distance of 432 km at the speed of 48 km/hr. In how many hours will the car cover this distance?

### Concept & Time Calculation The fundamental formula relating distance, speed, and time is that time is equal to the total distance divided by the speed. $$ \text{Time} = \frac{\text{Distance}}{\text{Speed}} $$ ### Step-by-Step Solution * **Given:** Distance = 432 km, Speed = 48 km/hr. * **Calculation:** Substitute the given values into the formula. * $\text{Time} = \frac{432}{48}$ * Simplify the fraction by dividing the numerator and denominator by 12: $432 / 12 = 36$ and $48 / 12 = 4$. * $\text{Time} = \frac{36}{4} = 9$ hours. ### Exam Strategy & Shortcut Use the unit digit strategy to quickly find the answer without full division. You need a number that, when multiplied by 48, ends in 2 (since the distance is 432). Looking at the options: $6 \times 8 = 48$ (ends in 8), $7 \times 8 = 56$ (ends in 6), $9 \times 8 = 72$ (ends in 2). Only 9 yields the correct unit digit. ### Common Pitfall A common mistake is trying to perform long division mentally and making a calculation error. Relying on fraction simplification or the unit digit method prevents these arithmetic mistakes. ### Final Answer Therefore, the correct answer is **9 hours**.