Abox contains 7 plain pencils and 5 pens. a second box contains 2 color pencils and 6 crayons. one item from each box is chosen at random. what is the probability that a pen from the first box and a crayon from the second box are selected?

the probability that a pen from the first box is selected
= total number of pens in 1st box/total number of objects in box 1
= 5/12

the probability that a crayon from the second box is selected 
= total number of crayons in 2nd box/total number of objects in box 2
= 6/8 = 3/4

All you have to do is multiply