John mows 247 square feet of lawn per minute. how many square yards of lawn does he mow per hour?

1647. 1 hour=60 minutes. John can mow 247 square feet per minute, so he can mow 60*247=14820 square feet per hour. 1 yard=3 feet, so 1 square yard = 3^2=9 square feet, so in the same duration of time, John can mow 14820/9=1647 square yards (approximately) per hour.