6. A jaw crusher is producing 150 tons/h of crushed gravel and discharging it onto a three screen deck. The top screen in the deck is a 2 in screen. The gradation of the crusher output shows passing 3 in, 89% passing the 1% in and 75% passing the 1 in. Material weight is 105 1b/cu ft. Find the minimum size of the 2 in screen to be used.