20 math i will be marking show all of your work

Letter A:

There is a 42.857143% chance of picking a black marble out of the bag. This is because there are 7 marbles total and 42.857143% of them(3/7) are black, so that is the probability.

Letter B:

There is a 14.285714% chance of picking this. The chance of picking a black black marble first is 3/7, which you multiply by the chance of picking a marble out on your second try without putting the first black marble back in ,which is 1/3. That gives you 1/7, or the percent above.

Letter C:

The probability of picking a black marble, replacing it, then picking another black marble is 18.367347%, or 9/49. You take the probability of picking out a black marble first, 3/7,  and multiply it by the chance of picking another black marble after replacing the first one, which is also 3/7.

Letter D:

The probability is different for B and C because in B the chance for the second one is less because for the second pick there are less marbles and a third of them are black. In C the chance of picking a black marble in the second is the same as in the first because you are putting the original back in.

i think it might be a but you might want a second opinion

hi there!

first we need to find out how much they are adding to each number to make the next number.

ex: 4 + 4 = 8, 8 + 8 = 16, and so on.

so continuing with 32,

32 + 32 = 64

64 + 64 = 128

128 + 128 = 256

256 + 256 = 512

4, 8, 16, 32, 64, 128, 256, 512

the 8th term of the sequence will be 512

hope this ! ~