- Messages
- 300
- Reaction score
- 138
- Points
- 53
For a blue pen to be in the left pocket once operation T takes place, a red pen must've been chosen from the left pocket followed by red pen from right pocket (1st) OR a blue pen chosen from left pocket and a blue pen chosen from right pocket(2nd).
For 1st scenario: (3/4)*(4/5)=0.6
2nd: (1/4)*(2/5)=0.1
0.6+0.1=0.7