Question

A box contains 7 plain pencils and 5 pens. A second box contains 5 color pencils and 5 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?

Answer 1

7 + 5 to get your total for rhe first box so 12 is your denominator for the first box, and there are 5 pens so the fraction is 5/12 for the first one.

For the second box you do it the same way you did the first but with its number instead so 5 + 5 which is 10 so thats your denominator and your number of your crayons which is 5 is on top. So your fraction for the second box is 5/10 which simplifies to 1/2. But if you have to get only one fraction add them together and you get 55/60 which simplifies to 11/12.
Hope this helped!