Alright! What name is your book and what page?
It is greater. You have to convert it to common denominators.
18/24 and 16/24. 18/24 is larger
We know 15 minutes contain 15*60 = 900 seconds, the time for 85 blinks
Then the time for each blink t = 900/85
Time elapsed in seconds for 51 blinks is then 51*t = 900*51/85 = 540 seconds
