Let E, F and G be three sets. State expressions for the events: only F occurs exactly two of the events occur plz explain ur answer Solution Only F occurs : E u F u G - E - G Explanation : EuFuG is the part tha is all of the circles. From this, i remove E and G, so only F remains. Exactly two of the events occur : (E n F) + (E n G) + (F n G) - 2*(E n F n G) ---> required expression Explanation : EnF is the part common to only E and F AND (all E,F and G) EnG is the part common to only E and G and (all E,F and G) FnG is the part common to only F and G and (all E,F and G) Since when all those were added, the (all E,F and G) was added thrice, i subtracted 2*(E n F n G) to get the required expression.