Answer:
A baby's heart beats 3600 times more in an hour than an adult's heart.
Step-by-step explanation:
If an adult's heart beats 2,100 times every 30 minutes, it beats 4,200 times every 60 minutes.
If a baby's heart beats 2,600 times every 20 minutes, it beats 7,800 times every hour.
Subtract the adult's heart beats from the baby's heart beats (7,800-4,200) and you'll receive the number of more beats a baby's heart does (7,800-4,200=3,600).
