Question:

Let \(H=\{1,15\}\) is a subgroup of a group of order \(8\). Then the number of all left cosets of \(H\) in \(G\) is

Show Hint

Number of left cosets of \(H\) in \(G\) is \(\dfrac{|G|}{|H|}\).
  • \(2\)
  • \(3\)
  • \(4\)
  • \(8\)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation

Concept:
The number of left cosets of a subgroup \(H\) in a group \(G\) is called the index of \(H\) in \(G\). It is given by \[ [G:H]=\frac{O(G)}{O(H)} \]

Step 1: Find the order of \(H\).
Given, \[ H=\{1,15\} \] So the number of elements in \(H\) is \[ O(H)=2 \]

Step 2: Write the order of \(G\).
The group \(G\) has order \[ O(G)=8 \]

Step 3: Find the number of left cosets.
\[ [G:H]=\frac{O(G)}{O(H)} \] \[ [G:H]=\frac{8}{2} \] \[ [G:H]=4 \]

Step 4: Final answer.
\[ \boxed{4} \]
Was this answer helpful?
0
0