A salesperson needs to visit 15 different offices during the week. In how many ways could she visit 3 different offices each day from Monday to Friday?

1 answer

Assuming the order within the day does not matter.

Monday: 15C3 ways
Tuesday: 12C3 ways
Wednesday: 9C3 ways
Thursday: 6C3 ways
Friday: 3C3 ways

Total= product of the above numbers,
=455*220*84*20*1
=168168000