The sun rises up at 7:30 in 25°E, What time will the sun rise up in 15°E? I've a question about time calculating.


  The sun rises up at 7:30 in 25°E, What time will the sun rise up in
  15°E?


What I've tried

$$25° - 15° = 10°$$

By the way

$$10° . 4 = 40 \space \text {minutes}$$ 

However, it seems wrong.
Your maths is not detailed, but you have the correct answer.

The Earth rotates at 15 degrees per hour (360 degrees/24 hours).

The time required to rotate 10 degrees is 10/15 = 0.666 hours, which is 40 minutes.