Improper because the top is supposed to be lower than the bottom
To find the probability that she develops lung cancer given that she smokes, multiply the two probabilities together:
4/9 x 3/10 = (4 * 3) / (9*10) = 12/90 = 2/15
' 36 = 9k ' is not an inequality. It's an <u>equality</u>, usually called an <em><u>equation</u></em>.
It's true whenever 'k' is 4, and false at any other time.
(You can determine that simply by dividing each side of the equation by 9.)