Which notation would be appropriate for calculating fewer than half of a group?

To determine the appropriate notation for calculating fewer than half of a group, it is important to understand the context of the choices provided. When evaluating the specific instance of a group containing 20 members, "fewer than half" would imply selecting less than 10 members from this group.

The notation “bC1” allows for the selection of one element from a subgroup comprising “b” elements. In conjunction with “(20-b)C1,” this notation expresses the selection of one member from the remaining elements after some have already been chosen. When combined, this notation effectively captures the idea of selecting a member from one group while accounting for those members not selected, aligning with the concept of choosing fewer than half from the total group of 20.

This method considers all potential combinations of selections, reflecting the flexible nature of choosing various subgroup memberships without exceeding the limit set by half of the total. Thus, it accurately represents the combinations needed to assess the selection process for fewer than ten members.