1) You and 3 friends go to a concert. In how many different ways can you sit in the assigned seats?
A) 6
B) 12
C) 24
D) 10
2) You own 7 pairs of jeans and want to take 2 of them with you on vacation. In how many ways can you choose 2 pairs of jeans?
A) 60
B) 21
C) 20
D) 10
9 years ago
9 years ago
Can someone please help me?!?!?!?!?!
9 years ago
(1)
Yes it's 24, because,
4 x 3 x 2 x 1 = 24 ways
(2)
You'll choose 2 pairs of jeans from 7 pairs. Order of the items does not matter, so we'll use combinations:
nCr = n! / ( r! (n - r)! )
Thus,
7C2 = 7! / (2! (7 - 2)! )
7C2 = 21
9 years ago
Thanks a bunch!!! (=
8 years ago
No, for #1 it starts at 3 not 4 (3x2x1 is the correct way) like you did. So it would be 6 for #1.
6 years ago
No, n. 1. does start at 4 because its You + 3 friends.
6 years ago
well done Hi, you got it wrong
5 years ago
probability unit test answers
1. d
2. a
3. c
4. c
5. b
6. d
7. c
8. d
9. b
10. d
11. a
12. b
13. a
14. d
15. d
16. b
if i got some wrong im sorry, these were just what i got.
7 months ago
1) To find the number of different ways you and your 3 friends can sit in the assigned seats at the concert, you can use the concept of permutations.
Since there are 4 of you, each with an assigned seat, there are 4 seats to fill. The first person has 4 options to choose from for their seat. After the first person has chosen a seat, there are 3 remaining seats for the second person to choose from. Once the second person has chosen a seat, there are 2 remaining seats for the third person to choose from. Finally, after the third person has chosen a seat, there is only 1 seat left for the fourth person.
Therefore, the total number of different ways you can sit in the assigned seats is given by the product of the number of options for each person: 4 * 3 * 2 * 1 = 24.
Therefore, the correct answer is C) 24.
2) To find the number of ways you can choose 2 pairs of jeans from a collection of 7 pairs, you can again use the concept of permutations.
Similar to the previous question, you have 7 options for the first pair of jeans you choose. Once you have chosen the first pair, there are 6 remaining options for the second pair. However, the order in which you choose the pairs does not matter. For example, choosing pair A and then pair B is the same as choosing pair B and then pair A.
To account for this, you need to divide the total number of options by the number of ways you can arrange the 2 pairs of jeans, which is given by 2 * 1 = 2.
Therefore, the total number of ways you can choose 2 pairs of jeans is given by the combination formula: 7 choose 2 = 7! / (2! * (7-2)!) = 7! / (2! * 5!) = (7 * 6) / (2 * 1) = 42 / 2 = 21.
Therefore, the correct answer is B) 21.