Question

Algebra Help Please!

(I can never get these!)
In how many ways can a teacher arrange 6 students in the front row if there are 30 total students?

Answer 1

does order matter?

Answer 2

Combinations, order doesn't matter - from 30 people choose 5... 30C5

if you don't know the formula:
http://www.mathsisfun.com/combinatorics/images/combinations-no-repeat.png

n is the total - 30 people. r is the number you're choosing - 5.

Answer 3

'arrange' suggests order to me

Answer 4

Order does not matter, I don't have a scientific calculator so it is difficult to d n!/r!(n-r)! in my head
@amistre64

Answer 5

do*

Answer 6

just do 30P6, divide by 6!


30.29.28.27.26.25
-----------------
6.5.4.3.2


29.28.27.26.25
--------------
4.3.2


29.7.4.9.3.13.2.25
----------------
4.3.2


29.7.9.13.25

Answer 7

I think G0.0gle could help with this problem :)

Answer 8

The answer wasn't on Google, thanks anyways!

Answer 9

29.63.13.25

(29.63).(13.25)

(20+9)(60+3).(13.25)

1200+27+30+540 . (10+3)(20+5)

(1797). 200+15+60 +50

(1797).(325)


1797
325
-----
8985
3594
5391
----------
584025

now to dbl chk lol

Answer 10

http://www.wolframalpha.com/input/?i=30+pick+6

i cant add apparently but it was close :)

Answer 11

1200+27+30+540
^^
spose to be 60, foiled by a typo

Answer 12

(1797+30).(325)

(1827).(325)


1827
325
-----
9135
3654
5481
----------
593775

got it lol

Answer 13

None of those are are one of my answer choices, I keep getting different numbers.
A. 171,001,720
B. 427,518,000
C. 657,720
D. 36

Answer 14

then lets try mine ..... where order matters

Answer 15

http://www.wolframalpha.com/input/?i=6%21*%2830+choose+6%29

427518....

Answer 16

k! * nCk = nPr .... so i just multipled the results without order by 6! to get w/order

Answer 17

Okay thank you so much! @amistre64

Answer 18

do i have to multiply it out by hand? :)

Answer 19

593775
720
---------

Answer 20

427,518,000?

Answer 21

thats what i get yes

Answer 22

That's what I got also after I caught along haha

Answer 23

:) good luck

Answer 24

Do you mind helping me with one more? @amistre62

Find the 7th term of the sequence whose nth term is given by the formula tn = n(n + 2).