2/6+3/6= 5/6
3/8+3/8= 3/4
1/4+1/4= 1/2
5/12+3/12= 2/3
Hope this helps
No -4/3 can not be simplified
There are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
<h3>What is permutation and combination?</h3>
A permutation is the number of different ways a set can be organized; order matters in permutations, but not in combinations.
We have:
A manager wants to select one group of 4 people from his 28 assistants.
The total number of groups possible = C(28, 4)

After calculating:
= 20475
Thus, there are, 20475 different groups are possible if the manager wants to select one group of 4 people from his 28 assistants.
Learn more about permutation and combination here:
brainly.com/question/2295036
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