This past Saturday, Jack worked for 3 hours mowing the lawn and doing chores in the house. Mowing the lawn burns 352 calories per hour and doing chores burns 136 calories per hour. If he burned a tota

This past Saturday, Jack worked for 3 hours mowing the lawn and doing chores in the house. Mowing the lawn burns 352 calories per hour and doing chores burns 136 calories per hour. If he burned a total of 570 calories, how long did it take him to mow the lawn?