If a person travels 150 km in 5 h, then he travels 210 km in_____h.

Options

A. 3
B. 4
C. 8
D. 7

Answer

To find out how many hours it takes for a person to travel 210 km when they travel 150 km in 5 hours, we can use the unitary method. Here’s a step-by-step solution:

### Step 1: Determine the speed of the person
First, we need to find out how fast the person is traveling. We can calculate the speed by dividing the distance traveled by the time taken.

\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{150 \text{ km}}{5 \text{ h}} = 30 \text{ km/h} \]

**Hint:** To find speed, remember the formula: Speed = Distance / Time.

### Step 2: Calculate the time taken to travel 210 km
Now that we know the speed, we can find out how long it takes to travel 210 km. We can use the formula:

\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} = \frac{210 \text{ km}}{30 \text{ km/h}} \]

**Hint:** To find time, use the formula: Time = Distance / Speed.

### Step 3: Perform the calculation
Now we can perform the calculation:

\[ \text{Time} = \frac{210}{30} = 7 \text{ hours} \]

**Hint:** When dividing, simplify the fraction by canceling out common factors.

### Conclusion
Thus, the person will take 7 hours to travel 210 km.

**Final Answer:** The person travels 210 km in 7 hours.

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