Chapter 1 - Measurement and Problem Solving - Learning Path Questions and Exercises - Exercises - Page 30: 37

15.0 min of arc.

The earth completes $360^{\circ}$ rotation in 24 hours, i.e., (360$\times$60) angular minutes in (24$\times$60) minutes. Since earth can rotate 21600 angular minutes in 1440 minutes, Minutes of arc rotated per minute=$\frac{21600}{1440}\,min\,of\,arc=15.0\,min\,of\,arc$