You should first calculate the number of minutes in a day. There are 60 minutes and hour, and 24 hours a day; multiplying these together will give you the total amount of minutes in a day:
60 * 24 = 1440
If you divide this by 3, you will get the amount of times a day the whale's heart beats 24 times:
1440 / 3 = 480. A grey whale's heart beats 24 times a day 480 times; multiply these together and have your final answer:
480 * 24 = 11520
Answer:
A grey whale's heart beats 11,520 times in a day.
Hope this helps!