- A450 : 1
- B9 : 2
- C20 : 9
- D9 : 20
Step-by-Step Solution
2 km = 2000 m, so the ratio is 900 : 2000. The HCF of 900 and 2000 is 100, giving 9 : 20. Comparing 900 with 2 without converting gives 450 : 1, and simply dropping the zeros gives 9 : 2 — both ignore that metres and kilometres are different units.
Answer: D) 9 : 20