Read the given information carefully and answer the given questions. There are five units i.e. 1, 2, 3, 4 and 5. Each unit has a different height. Also each unit contains books and boxes. unit2 is above unit1 and unit3 is above unit2 and so on. Every unit belongs to different country i.e. Beijing, Paris, London, Sydney and Zurich. The total height of all five units is equal to 252”ft. * Total Height of Unit is equal to the total height of books plus total height of boxes in each unit. * Height of books is not equal to the height of boxes. Unless specified so. The unit belongs to London is an even unit. The total height of unit1 is 75” ft. Sydney does not belong to unit1. The total height of unit, which belongs to Sydney is 55”ft. There is only one unit between the units which belongs to London and Paris. The height of books and height of boxes in unit3 are equal. The height of books in unit2 is not less than 30”ft. The height of books in unit4 is 4’’ft more than height of books which is in unit3. The total height of unit which belongs to London is not 37”ft. Unit which has 37’’ft will not be immediate above to unit which has 20’’ft more height than unit which belongs to Sydney . The height of boxes in unit2 is 23”ft. Unit belongs to Zurich does not equal height of books and boxes. The total height of unit2 is an odd number and more than 50”ft and less than 55”ft. Height of boxes in unit 1 is 23’’ft more than unit4. Height of books in unit 5 is 7’’ft less than unit 1. What is the height of box in unit 4?