Let's evaluate each statement one by one:
Statement A: 6.3 × 10^7 is approximately 20 times larger than 3.1 × 10^8.
Calculating both:
- 6.3 × 10^7 = 63,000,000
- 3.1 × 10^8 = 310,000,000
Now, dividing 3.1 × 10^8 by 6.3 × 10^7: 310,000,000 / 63,000,000 ≈ 4.92
This shows that 6.3 × 10^7 is not approximately 20 times smaller than 3.1 × 10^8. Statement A is false.
Statement B: 19.6 × 10^6 is approximately 65 times larger than 3.0 × 10^5.
Calculating both:
- 19.6 × 10^6 = 19,600,000
- 3.0 × 10^5 = 300,000
Now, dividing 19.6 × 10^6 by 3.0 × 10^5: 19,600,000 / 300,000 ≈ 65.33
This shows that 19.6 × 10^6 is approximately 65 times larger than 3.0 × 10^5. Statement B is true.
Statement C: 8.6 × 10^-6 is approximately 41 times larger than 2.1 × 10^-5.
Calculating both:
- 8.6 × 10^-6 = 0.0000086
- 2.1 × 10^-5 = 0.000021
Now, dividing 8.6 × 10^-6 by 2.1 × 10^-5: 8.6 × 10^-6 / 2.1 × 10^-5 ≈ 0.4095
This shows that 8.6 × 10^-6 is not approximately 41 times larger than 2.1 × 10^-5. Statement C is false.
Statement D: 5.9 × 10^-6 is approximately 28 times larger than 2.1 × 10^-7.
Calculating both:
- 5.9 × 10^-6 = 0.0000059
- 2.1 × 10^-7 = 0.00000021
Now, dividing 5.9 × 10^-6 by 2.1 × 10^-7: 5.9 × 10^-6 / 2.1 × 10^-7 ≈ 28.10
This shows that 5.9 × 10^-6 is approximately 28 times larger than 2.1 × 10^-7. Statement D is true.
Conclusion: The correct statements are B and D.