Question #7640c

1 Answer
Jul 22, 2017

Nine

Explanation:

23 years = 23 × 365 years = 23 × 365 × 24 × 3600 seconds

23 years = 725328000 seconds = 7.25328 × 10⁸ seconds

Order of magnitude of #a×10^b# when #a > 5# is #b + 1#

Therefore order of magnitude of 7.25328 × 10⁸ seconds is 8 + 1 = 9