Machine-translated by Google. Questions are authored in English.
Top

Discussion

What is the angle between the hour hand and the minute hand of a clock when the clock shows 10 hours 10 minutes ?

  • A.240°
  • B.130°
  • C.245°
  • D.120°

Answer: C

The angle is 245°, the reflex angle.

The angle between the hands at \(H\) hours \(M\) minutes is \(|30H - 5.5M|\).

\[ \begin{aligned} |30 \times 10 - 5.5 \times 10| &= |300 - 55| \\ &= 245^\circ \end{aligned} \]

The smaller angle between the hands is \(360^\circ - 245^\circ = 115^\circ\), which is not among the options, so the keyed answer is the reflex angle of 245°. 240° (or 120°) is what you get by leaving the hour hand fixed on the 10, forgetting that it moves 5° past it in 10 minutes.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.