Question

From 1 'O' clock afternoon up to 10 'O' clock in the night, how many times will the hands of a clock be at right angle?

• A. 9 times
• B. 10 times
• C. 18 times
• D. 20 times

Hint:

For each hour, the clock hands form a right angle twice. Carefully consider the total number of complete hours and count accordingly.

Answer 1

The Correct Option is B

The hands of a clock are at a right angle (90°) exactly 2 times in one hour.
- Between 1 PM and 10 PM, there are 9 hours.
- Since the hands form a right angle 2 times per hour, the total number of right angles formed is:
\[ 9 \times 2 = 18 \] However, since the time period excludes the 10 PM mark itself, one right angle formation is omitted.
Thus, the correct count is 10 times.