Question

When the time by the watch is $20$ minutes past $7$, the angle between the hands of the watch is.

• A. ${100}^o$
• B. ${90}^o$
• C. ${80}^o$
• D. ${95}^o$

Answer 1

Answer: (A)

${100}^o$

At $7$ o'clock, larger angle between minute hand and hour hand is ${30}^0\times 7={210}^0$.

In $20$ minutes, hour hand moves by $20\times {\frac{1}{2}}^0={10}^0$ and minute hand moves by ${120}^0$.

So, the smaller angle between hour hand and minute hand is

$={210}^0+{10}^0-{120}^0={100}^0$