Question

i just need someone to check my answer.
Jocelyn needs to study two stars for her astronomy research. She has narrowed her choices down to four stars that are located on a straight line from earth. Jocelyn wants to study the two stars that are closest to each other. Which two stars should she study?
and here i solved them vvvv
Star A | 0.176 * 10^18 km 176000000000000000
Star B | 22.13*10^16 km 221300000000000000
Star C | 31*42*10^14 km 3142000000000000
Star D | 125.5*10^15 km 125500000000000000
I chose A and D.
It then also asks
"What is the distance between the two stars? Explain your strategy"
and i put "I solved the answers and once I got the numbers closest to each other i subtracted them to get 50500000000000000"

If i'm wrong can you correct my mistakes?

Answer 1

well actually it would be a and be because the difference is only 453 where the difference of a and d would be 505

to the second question 
the difference between the two stars is 453 kilometers