Identify whether each statement represents, direct variation, inverse variation, joint variation.
1. Electric bills depend on the number of electric appliances in use.
2. For the same total expenses, the share of one person depends on the number of persons in the group.
3. The speed of a car is related to the time to make a trip.
4. A cone of volume (V) varies jointly as the square of the radius and height of the base 5.The number of persons sharing a cake is related to the size of the slices.
6. The number of gallons of gasoline is related to distance travelled by a car.​