Question

After Hillary realized her clock was running 30 minutes fast, she used a knob on the clock to turn the minute hand back 30 minutes. Which describes the rotation of the minute hand?
180 degrees clockwise rotation
90 degrees clockwise rotation
90 degrees counterclockwise rotation
180 degrees counterclockwise rotation

Answer 1

Answer: 180 degrees counterclockwise rotation

Step-by-step explanation:

Given: The clock was running 30 minutes faster.

To correct it Hilary turn the minute hand back 30 minutes, which means a anticlockwise rotation.

We know that a full rotation in a clock is of $360^{\circ}$.

Total time taken by minute hand to complete the rotation is 60 minutes.

Therefore,

$60\ minutes=360^{\circ}\\\Rightarrow1\ minute=\frac{360^{\circ}}{60}\\\Rightarrow30\ minutes=\frac{360^{\circ}}{60}\times30\\\Rightarrow\ 30 minutes= 180^{\circ}$

Hence, the rotation of the minute hand is 180 degrees counterclockwise rotation.

Answer 2

180 degrees counterclockwise because 360 degrees is a full circle and 180 is half a circle because 6x2=12