Answer:
1/10 or 10%
Explanation:
Volunteer one, two, three, four and five
There are many pairings, they are;
One + two,
One + three,
One + four,
One + five,
Two + three,
Two + four,
Two + five,
Three + four,
Three + five,
Four + five.
This means there are 10 possible pairings.
This shows that the chances both you and your friend will be chosen is 1/10
Hope that helped :)