Well, the problem is that he does not replace the first marble after he draws it. Therefore, yes, he has a 2/12 probability of drawing a yellow marble first, but then he has a 4/11 probability of drawing a red marble second, not 4/12. This is because there are going to only be 11 marbles left in the bag after he draws the first marble and does not replace it.
The correct answer would be:
(2/12)(4/11)=8/132=4/66=2/33
This one is easy all you have to do is subtract the 2.25 by the 15 to get 12.75.
The equation is:
20,000 * e^(0.15 t) = 28,000
e^( 0.15 t ) = 28,000 : 20,000
e^( 0.15 t ) = 1.4
0.15 t = ln 1.4
0.15 t = 0.3365
t = 0.3365 : 0.15
t = 2.24 ≈ 2
Answer:
A ) 2 years.
