Statements-
1.All bulbs are tubes.
2.Some tubes are knives.
3.All knives are frames.
4.Some frames are bulbs.
Conclusions.
1. Atleast some bulbs are frames.
2. Some tubes are not knives.
3. All frames being tubes is a possibility.
Some frames are bulbs(I) ⇒ Conversion ⇒ Some bulbs are frames(I). Hence conclusion I follows. Some tubes are knives(I) ⇒ Conversion ⇒ Some knives are tubes(I). Hence conclusion II does not follow. Some tubes are knives(I) + All knives are frames(A) ⇒ Some tubes are frames(I) ⇒ Conversion ⇒ Some frames are tubes (I) ⇒ Probable conclusion ⇒ All frames being tubes is a possibility(A). Hence conclusion III follows. Alternate Method: