In how many ways can three different letters be selected from the lett...
Step 1: Understand the objective
The objective of the question is to find the number of ways in which three different letters can be SELECTED from a set of 4 letters: T, H, R and E.
(Please note that the word THREE has 5 alphabets, but of these, E occurs twice. So, we get only 4 different alphabets from the word THREE: T, H, R and E)
Step 2: Write the objective equation enlisting all tasks
This is a Selection question. Order doesn’t matter here. So we will solve it by using the nCr formula.
In this case, only one task needs to be completed to accomplish the objective: Select 3 letters out of the given set of 4 different letters.
So, the objective equation becomes:
(Number of ways of selecting 3 letters out of 4 different letters) = 4C3
Step 3: Determine the number of ways of doing each task
By using the formula:
We get:
Upon simplifying this expression, you get
4C3=4
Step 4: Calculate the final answer
By putting this value in the objective equation, we get:
(Number of ways of selecting 3 letters out of 4 different letters) = 4
Answer: Option A