Abox contains 9 plain pencils and 3 pens. a second box contains 3 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?

2 You have 5 chances in 8 of pickin a colored pencil ===> 5/8 

3. The probability of doing both is the product of the two ===> 1/4 * 5/8 = 5/32

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.