Posted by **Shay** on Monday, August 25, 2008 at 4:49pm.

seven people meet and shake hands with eachother- how many handshakes occur?

(second question)

using inductive reasoning, write a formula for the number of handshakes if the number of people is n

- Math -
**Damon**, Monday, August 25, 2008 at 6:57pm
combinations of n objects taken r at a time

C(n,r) = n!/[r!(n-r!)]

C(7,2) = 7!/[2!(5!)]

=7*3

=21

ok, reasoning

first person shakes with 6

second person with 5

third with 4

.

.

.

6th with 1

so

6+5+4+3+2+1 = 21 sure enough

## Answer this Question

## Related Questions

- Geometry (sorta) - seven people meet and shake hands with eachother- how many ...
- Education Psychology - Steve ponders a math problem that asks for the number of ...
- Algebra - A scientist wants to research the potential spread of germs by contact...
- Math - On the first day of school everyone wants to shake hands. How many ...
- math - If 8 people went to a party and each person shook hands at least one time...
- Math - A sociology seminar has 7 members (a) They begin each meeting with each ...
- math - How many people were at a party if There were 105 handshakes at a party ...
- MAth - 14 students in an Algebra class were asked to shake hands with each other...
- math - At the faculty costume party, each teacher from Transylvania Middle ...
- maths - Please help. Thank you Fourteen people attend a meeting. If each person ...