quick perm q (1 Viewer)

[shkspeare]

hi could some1 tell me how to do this

"how many even numbers of 4 digits can be formed with the figures 3,4,7,8" if repetitions ARE allowed

i dont know how to answer perm questions in general if they say repetitions are allowed =(

thx guys

an explanation of ur working will b helpful too!

 

[mojako]

By inspection, there are 32 possible numbers.

If repetition is allowed, you basically don't use the factorial notation
just times, times and times (and use power if there are many letters)

for ur Q, for the number to be even it must ends with either 4 or 8 right?
choose:
1st digit * 2nd digit * 3rd digit * 4th digit
4 * 4 * 4 * 2
(the first digit can be anything from the four)
(the second digit can also be anything from the four)


now, another simple questions:
-> how many ways can we arrange the letters in "english" if repetition is allowed?
the answer will be 7⁷

-> how many 7-letter words can we form from the english alphabet, if repetition is allowed?
answer: 26⁷

 

[Rorix]

dudes, perms are for women.

 

[ngai]

how many 7-letter words can we form from the english alphabet, if repetition is allowed?
answer: 26⁷

hmm...i see
just wondering, wat does the word acizdjy mean?

 

[Li0n]

hmm...i see
just wondering, wat does the word acizdjy mean?

same with the word ROFLMAO and KEKEKEk

 

[mojako]

Oh, "word", within the context of the probability questions asked in the HSC mathematics courses (including extension courses), is defined as any letters grouped next to each other.
Don't you learn to read texts in thei contexts in the HSC english courses? You're meant to apply the skills you learn in one subject in your life, and part of your life is doing the HSC mathematics courses so you are really expected to be able to do so.
Oh, and "text" is anything which you can read and/or you can see: articles, advertisements, exam questions, movies, plays....