An adult blinks about 450 times in 30 min. A 12 year old blinks about 150 times in 15 min. How many more times does an adult blink in 60 min. than a 12 year old?

150x2 because 15 minutes is half that of 30

=300

then times that by 2 again to get an hour so 600

then times 450 by 2 to get an hour so 900

then subtract 600 from 900 which is 300

300 more times is your answer