The oldest painting in the museum is 225.75 years old. If the painting is washed for 15 times, the time span between the consecutive washings is .
The internal dimensions of a room are 15 m x 9 x 5 M the measurement of a door in the room are 2 X 1 m find the total cost of painting the four walls of the room if the cost of painting is a 80 permit square