Question

Galaxy a is 10 mpc away and galaxy b is 30 mpc away. which of the followings is true?

1. galaxy a is moving away from us three times as fast as galaxy b
2. galaxy a is moving away from us one-third as slow as galaxy b
3. galaxy b is moving away from us nine times as fast as galaxy a
4. galaxy b is moving toward us three times as fast as galaxy a

Answer 1

The correct answer is option 2. Galaxy A is moving away from us one-third as slow as Galaxy B.

Step-by-step explanation:

To determine which statement is true, we can compare the distances and speeds. If Galaxy A is moving away from us three times as fast as Galaxy B, then the speed of A must be three times the speed of B. Since the distance between A and us is 10 Mpc and the distance between B and us is 30 Mpc, we can compare the ratios of the distances and speeds.

In this case, the ratio of the distances is 1/3, and the ratio of the speeds must be the same for the statement to be true. So, Galaxy A is moving away from us one-third as slow as Galaxy B. Therefore, the correct statement is option 2: Galaxy A is moving away from us one-third as slow as Galaxy B.