Question

a box contains 5 plain pencils and 5 pens. a second box contains 7 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

First box: $\dfrac{pen}{total}=\dfrac{5}{10}=\dfrac{1}{2}$

Second box: $\dfrac{crayon}{total}=\dfrac{5}{12}$

Multiply them:

$\dfrac{1}{2}*\dfrac{5}{12}=\dfrac{5}{24}$

The probabilityis $\dfrac{5}{24}$