Where will the hour hand of a clock stop, if it starts from 7 and turns through 3 right angles ?

Options

A. 2
B. 3
C. 4
D. 5

Answer

To solve the problem of where the hour hand of a clock will stop after starting from 7 and turning through 3 right angles, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Right Angles**:
- A right angle is equal to 90 degrees. Therefore, three right angles would be:
\[ 3 \times 90^\circ = 270^\circ \]

2. **Calculating the Movement of the Hour Hand**:
- The hour hand of a clock completes a full circle (360 degrees) in 12 hours. This means that for every hour, the hour hand moves:
\[ \frac{360^\circ}{12 \text{ hours}} = 30^\circ \text{ per hour} \]

3. **Finding the Time Taken to Turn 270 Degrees**:
- To find out how many hours it takes to turn 270 degrees, we can set up the following equation:
\[ \text{Time (in hours)} = \frac{270^\circ}{30^\circ \text{ per hour}} = 9 \text{ hours} \]

4. **Determining the Final Position of the Hour Hand**:
- Starting from 7 o'clock, if we move forward by 9 hours, we can count the hours:
- 7 o'clock + 1 hour = 8 o'clock
- 8 o'clock + 1 hour = 9 o'clock
- 9 o'clock + 1 hour = 10 o'clock
- 10 o'clock + 1 hour = 11 o'clock
- 11 o'clock + 1 hour = 12 o'clock
- 12 o'clock + 1 hour = 1 o'clock
- 1 o'clock + 1 hour = 2 o'clock
- 2 o'clock + 1 hour = 3 o'clock
- 3 o'clock + 1 hour = 4 o'clock

- Therefore, after moving 9 hours from 7 o'clock, the hour hand will stop at 4 o'clock.

### Final Answer:
The hour hand will stop at **4 o'clock**.

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