Question

When testing for current in a cable with sixsix ​color-coded wires, the author used a meter to test threethree wires at a time. How many different tests are required for every possible pairing of threethree ​wires?

Answer 1

20 tests

Explanation:

There are six different wires, and for each test the author picks three, this means that each test is a combination of three out of six wires (₆C₃) . The number of total combinations possible is given by:

`_6C_3=(6!)/((6-3)!3!)\\_6C_3=(6*5*4)/(3*2*1)\\_6C_3=20`

20 tests are required to verify every possible pairing of three wires.