There are three pillars X,Y and Z of different heights. Three spiders A, B and C start to climb on these pillars simultaneously. In one chance, A climbs on X by 6cm but slips down 1cm. B climbs on Y by 7 cm but slips down 3 cm. C climbs on Z by 6.5 cm but slips down 2 cm. If each of them requires 40 chances to reach the top of the pillars, what is height of shortest pillar?

Two walls and ceiling of a room meet at right angles at a point P. A fly is in the air 1m from one wall, 8 m from the other wall and 9 m from point P. How many meters is fly from ceiling?