Question 1017445

p(both studying physics)=(8/30)(7/29)=28/435
P(biology1 chemistry2)=(12/30)(10/29)=4/29
P(same subject)=28/435 (or 56/870) + (10/30)(9/29)+(12/30)(11/29)=
(56+90+132)/870=
(278/870)=(139/435)