If a quality control check is made by inspecting a sample of 2 light bulbs from a box of 12 light bulbs, how many different samples can be chosen
6, 24, 36, 66, 72
6, 24, 36, 66, 72
We're choosing 2 lightbulbs from 12 lightbulbs.teejaycrown wrote:If a quality control check is made by inspecting a sample of 2 light bulbs from a box of 12 light bulbs, how many different samples can be chosen
6, 24, 36, 66, 72
Since the order in which the lightbulbs are selected does not matter, this can be handled using combinations.
So, we can select 2 lightbulbs from 12 lightbulbs in 12C2 ways ([spoiler]= 66 ways = D[/spoiler])
Aside: If anyone is interested, we have a free video on calculating combinations in your head: https://www.gmatprepnow.com/module/gmat-counting?id=789
Cheers,
Brent
