Question

The math test has 10 multiple choice questions, each with 3 answers. Betty guesses correctly on the first 3 questions.

What is the probability that she will guess correctly on the fourth question?
a)1/10 b)1/4 c)1/3

Answer 1

Hint: each event is independent (ie answering correctly on one problem has no affect on the others). Sure some tests have dependent problems, but let's assume each event is independent.

Answer 2

ok.....and

Answer 3

so just focus on problem #4 alone

what are the chances of getting it right

Answer 4

1/10?

Answer 5

there's one way to get it right, but are there 10 choices?

Answer 6

1/4?

Answer 7

are there 4 choices?

Answer 8

so theres three choices to choose from

Answer 9

1/3

Answer 10

yep, 1/3