A team of 3 students needs to be selected from a class of 10 students. However, two specific students, John and Sarah, cannot be on the team together. In how many ways can the team be formed?
42
56
18
26
Number of ways to select 3 students from 10 without John and Sarah together:
Selecting John:
We need to select 2 more students from the remaining 8 (excluding John and Sarah). This can be done in ways, where
represents the number of combinations of selecting
items from a set of
items.
Selecting Sarah:
Similarly, we need to select 2 more students from the remaining 8 (excluding John and Sarah). This can also be done in ways.
Hence option 2 is correct.
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