Question

A course meets 5 times a week. One student misses class 2 days apart. A second student misses class 7 days apart. They were both absent on the second day of class. What is the next class day when both will be absent again?

Answer 1

@Directrix

Answer 2

I don't know what "misses class 2 days apart" means. Two consecutive days or two days which are not consecutive.

Answer 3

@Daniellelovee

Answer 4

this is an example I found online very similar
A course meets 5 times a week. One student misses class 3 days apart. A second student misses
class 7 days apart. They were both absent on the second day of class. What is the next class day
when both will be absent again?
A) class 22 B) class 10 C) class 21 D) class 23
and it says that the answer for that question is D

Answer 5

but how did they get to that answer?

Answer 6

give me a second please

Answer 7

this one is being difficult

Answer 8

yeah i know i can't figure it out

Answer 9

maybe with the information of the example that I gave you Directrix might be able to help you he/she is way more intelligent than me especially in math :)

Answer 10

@Directrix

Answer 11

@wio

Answer 12

I'd just use a calendar, seems like it'd be easy enough.

Start on a Tuesday, that would be the 2nd day of class when they both miss.

Answer 13

okay then what do i do after?

Answer 14

like i dont know what to subtract

Answer 15

You don't subtract anything. Start on a Tuesday, skip two days of class and then that's the next day missed.

Do the same with the other person, start on a Tuesday, skip 7 days of class and that's their next day missed. Keep going until they miss the same day.

Answer 16

what answer do you get ?

Answer 17

the answer is supposed to be day 16 but im not getting that

Answer 18

i have to go to bed but if you figure out how to do it please just post it here

Answer 19

Nvm I can stay loner

Answer 20

I followed what I interpreted from @agent0smith 's instructions and got this. See attachment.

Answer 21

@Directrix I think you only skipped 6 days the second time, not 7. But yeah that's how to do it, I think.

Answer 22

Why are we starting on Tuesday? Doing that gave me the 17th day of class.

Answer 23

Okay, I'll try again. Thanks.

Answer 24

Second day of class would be a Tuesday.

Answer 25

I am beyond the 16th day of class here.

Answer 26

@Daniellelovee Where is the explanation for the example problem you posted? Just wondering.

Answer 27

I think you only skipped 6 days again.

Answer 28

I am hung up in a loop. I'll try again.

Answer 29

I'm not even sure about the question. If it means "7 days apart" as in 7 days, or 7 actual class days. Pretty poor question all around.

Answer 30

I think the problem is meant to be a least common multiple problem maybe.
I don't know what "apart" means in this setting.

Answer 31

It's a lame excuse for a word problem, I think. I guess it is a least common multiple problem, but is all screwed up by the wording and days. It's possible 7 days apart means 1 missed class, skip 6 classes, then another missed class. But your last looks right.

Answer 32

That does give day 16.

Answer 33

So it's a LCM problem, since that'd be 14 days after the first miss.

Answer 34

So, going back to this question, is it possible to get 23 without drawing on the calendar?

A course meets 5 times a week. One student misses class 3 days apart. A second student misses class 7 days apart. They were both absent on the second day of class. What is the next class day when both will be absent again?

Answer 35

I think I'll have to go back to the calendar.

Answer 36

Yeah, now that we know what the wording means. LCM of 7 and 3 is 21, so 21 days after day 2.

Answer 37

That is great thinking. I was still hung up on apart and did 6*2 + 2 which was a bust.

Answer 38

On the original problem, then find the least common multiple of 2 and 7 to get 14 and then add 2 for the second day of class both missed to get 14 + 2 = 16 as answer.

Sorry to be repeating your words but I am trying to brand this on my brain.

Still, it is a poorly written question. It tore my brain "apart."

Answer 39

lol, clever

Answer 40

Thanks. @agent0smith

Answer 41

And yes that's how I'd guess you're meant to do it, with the LCM of 2 and 7, and add day 2.

Answer 42

I guess even if it's interpreted the way we originally did, you could use LCM.

It would be the LCM of 8 (not 7) and 3 (not 2). LCM is 24, add day 2 - so day 26. Which matches the answer we originally agreed on, with your calendar.

Answer 43

Without the answer the OP provided, I would have thought day 26.
Apart from "apart," this thread has been fun if slightly frustrating.
I enjoyed it. Thanks.

Answer 44

Yeah, it's always fun when a question takes on a life of its own like this.