The angle between the minute hand and the hour hand of a clock when the time is 4.20, is
(a)0°
(b)10°
(c)5°
(d)20°
Answer
Answer (as printed): B
Explanation
Angle traced by hour hand in $$\frac{13}{3} \mathrm{hrs}=\left(\frac{360}{12} \times \frac{13}{3}\right)^{\circ}=130^{\circ} .$$ Angle traced by min. hand in 20 min. $=\left(\frac{360}{60} \times 20\right)^{\circ}=120^{\circ}$. $$\text { ∴ } \text { Required angle }=(130-120)^{\circ}=10^{\circ} .$$
Explanation as extracted from the printed page; notation may be imperfect.