69.1k views
5 votes
In how many ways can you arrange seven items, taking only 3 at a time?

User Mikeck
by
8.1k points

2 Answers

6 votes

Answer:

7 items in 2 ways remains 1

Explanation:

7 ÷3 = 2.3

7=$$$$$$$

3 =$$$

3 =$$$

1 =$

User Cublax
by
7.4k points
1 vote

Answer:

To arrange 7 items, taking only 3 at a time and assuming that the order of those 3 items do not matter, the procedure is as below:

You first pick 3 items out of 7 original items (combination with n = 7 and k = 3), then you pick 3 items out of 4 remaining items (combination with n = 4 and k = 3), the last item is automatically chosen.

=> Number of ways to do this:

N = 7C3 x 4C3

= 7!/(3! x (7-3)!) x 4!/(3! x (4 - 3)!)

= 35 x 4

= 140 ways

Hope this helps!

:)

User John Coleman
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories