To solve this first we have to find out how many seconds are in 15 minutes.
So, 15 x 60 since there is 60 seconds in a minute, and of course there are 15 minutes.
15 x 60 = 900 seconds.
Now we need to find out about how many seconds does it take George to blink once. So we divide 900 seconds by 85 blinks.
900 / 85 = About 11 seconds for one blink.
Now we use the rate of 1 blink = 11 seconds and multiply. Since they said 51 blinks you would multiply 51 blinks by 11 seconds.
51 x 11 = About 561 seconds.
Answer: About 561 seconds passed in 51 blinks.