Sample space of A the 1st box ={5 plain pencils, 5 pens}
Sample space of B the 2nd box ={5 color pencils,7 crayons}
P(pen from the first box) =5/10 = 1/2
P(crayon from the second box) = 7/12
Now the P(pen from the first box AND crayon from the second box)
=P(pen from the first box ∩ crayon from the second box) =1/2 x 7/12
= 7/24 = 0.29