avaneeshvyas wrote:
In a Question paper there are 4 multiple choice questions. Each question has 5 choices with only one choice as the correct answer. What is the total number of ways in which a candidate will not get all the four answers correct?
A. 19
B. 85
C. 120
D. 624
E. 1024
Let's first determine the TOTAL number of ways the test can be completed.
The 1st question can be answered in
5 different ways (A, B, C, D, or E).
The 2nd question can be answered in
5 different ways (A, B, C, D, or E).
The 3rd question can be answered in
5 different ways (A, B, C, D, or E).
The 4th question can be answered in
5 different ways (A, B, C, D, or E).
By the Fundamental Counting Principle (FCP), the total number of ways we can complete test = (
5)(
5)(
5)(
5) =
625 ways
So, there
625 possible outcomes
Among those
625 possible outcomes,
ONLY 1 outcome is such that all four questions ARE answered correctly.
This means, in the remaining
624 outcomes, the four questions are NOT all answered correctly.
Answer: D
Cheers,
Brent
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