Question

A box contains 4 plain pencils and 4 pens. A second box contains 3 color pencils and 7 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?Write your answer as a fraction in simplest form.

Answer 1

P ( pen from first box) =  4/8 = 1/2
P(crayon from second box) = 7/10

as these events are independent the individual probabilities are multiplied 
so P( pen and crayon) = 1/2 * 7/10 = 7/20