JAMB 1992 · UME · Q49
Five people are to be arranged in a row for a group photograph. How many arrangements are there if a married couple in the group insist on sitting next to each other?
Worked solution (try it first)
- Tie the couple together and treat them as one unit.
- Then there are 4 units to arrange in a row: ways.
- Inside the unit the couple can swap places: ways.
- Multiply: arrangements, option A.