I really need this broke down. I am not getting the same answers as other tutors :/

If I am taking a 10 item multiple choice test that has 4 alternative choices on each question and I must pick only one answer, and I am only guessing on the whole test, and if answering one question is independent of answering the others, find the probabilities of the following events.

a.8 or more correct

b.1 or more correct

c.5 correct

d.0 correct

e.less than 3 are correct

You want to know whether a friend's child can tell the difference between a circle and a square block. You have 2 circle blocks and 2 square blocks. You line the blocks up randomly and ask the child to pick out the circle block. After a block is picked you replace it and randomize the order of the blocks once more. You repeat this procedure of asking the child to pick out the circle block 10 times. If he cannot tell the difference between a circle and a square block, what is the probability he will pick a circle block at least 8 times?