Answer with explanation:
Relation between Speed , Distance and time
Distance =Speed × Time
→It means Speed is inversely Proportional to time.
As distance will remain constant , in that frame of reference
If speed of light in a Medium
![=s=3 * 10^8 \frac{\text{meter}}{\text{second}}](https://img.qammunity.org/2020/formulas/mathematics/high-school/scy8bdxxmp361yuaohl8exr9wwyf2cf3ba.png)
Then, time taken to cross the medium = t seconds or hours or another unit of time.
Now, If speed of light is 50% of the speed of light relative to us
That is Speed of light in another medium
![=w=(50)/(100) * 3 * 10^8\\\\=1.5 * 10^8 \frac{\text{meter}}{\text{second}}](https://img.qammunity.org/2020/formulas/mathematics/high-school/1ogowrojlgfm8l2luy7vfgx5iydy3op318.png)
Then, time taken to cross the medium = 2t seconds or hours or another unit of time.
Using Unitary Method
![\rightarrow v_(1)* t_(1)=v_(2) * t_(2)\\\\1.\rightarrow 3 * 10^8 * t=(50)/(100) * 3 * 10^8 * t_(1)\\\\t_(1)=2t\\\\2.\rightarrow 3 * 10^8 * t=(99.5)/(100) * 3 * 10^8 * t_(2)\\\\t_(2)=(1000t)/(995)\\\\t_(2)=(200t)/(199)](https://img.qammunity.org/2020/formulas/mathematics/high-school/t9sd0h2a9w0fy9i3dyl45utujfwued7uij.png)