At first there are three marbles for Sam to pick from. the possibility of drawing a colored marble is 2/3. if Sam picks one of the colored marbles, the possibility of therefore (if he'd drawn the colored marble) drawing the second colored marble is 1/2. for the possibility of those happening consequently, we have to multiply the possibilities. 2/3 * 1/2 is 2/6 is 1/3. which means Sam wins in 33.333...% cases. Julie has a better chance of winning.
adding a white marble would change the possibilities to 1/2 and 1/3 consequently, meaning Sam wins in 1/2 * 1/3 = 1/6 = 16.7% cases, which is even less fair.
adding a colored marble would change the possibilities to 3/4 and 2/3 consequently, meaning Sam wins in 3/4 * 2/3 = 6/12 = 50% cases, which finally makes the game fair.
It should be d. , Because if you take the equation 3x+y=9, and make it slope intercept form, it would be y= -3x+9. -3 is the slope, and 9 is the y intercept. D is the answer.
The best way to estimate it is to do "written addition" in your head, adding 1+8, then 9+3, all the way until you get to the front. the actual answer is 189,459, so your answer should be somewhere close to that.