quick easy matrices question

[vidang]

In Question 4d
why is it they sub in T^4 but not T^5

when I sub in T^5 multiple by So
i get:
285.992
214.008
but thats incorrect

when you sub in T^4
you get the answer they they have given me here

anyone wanna answer why you must make T to the power of 4 or is the abck of the book wrong? LOL :\

[physics]

i think its the counting thing. LIke S0 is the original first state thingo and that is eg s0=janurary and then feburary is S1 and  in march it would be like S2 instead of S3(because march is the 3rd month)
if u know what i mean.

[f.sharp]

first week is week 0.

[jasoN-]

Doesn't make sense to me.
The solution to c is S0 x T [equivalent S0 x T^1].
If S0 x T is next week, then logically S0 x T^5 is after 5 weeks
All I can think of is 'after 5 weeks' includes the first week (or current week).

[TyErd]

first week is week 0.

yeah So = week 1
         S1 = week 2
         S2 = week 3
         S3 = week 4
         S4 = week 5

and the formula says Sn = T^n  * So

therefore because S4 will find us week 5 it becomes S4 = T^4 * So

if you read part b, it says So should describe the first week.

[vidang]

thanks :]

[mojomojo]

But shouldn't we assume that it's 5 weeks after the given week?
As we've got the information for the first week and it says xxx members "used".... it also means that week has ended.. so when the question is asking after 5 weeks, shouldn't we calculate the 5th week starting from the end of the given week?

That's what I usually do for the Cambridge text book. :S

[TyErd]

when it says after 5 weeks, it means 5 weeks including the current week.

         So = after 1 week
         S1 = after 2 weeks
         S2 = after 3 weeks
         S3 = after 4 weeks
         S4 = after 5 weeks

but yeah mojomojo i understand your concern, the questions are pretty ambiguous and I doubt they can give you a question that is this vague in the exam.

[vidang]

LOL they gave me this question in my matrices sac question was very very similar and i subbed 4
 but answer was sub in 5 LOLOL
only marks i lost
there goes a perfect score fml

[mojomojo]

LOL they gave me this question in my matrices sac question was very very similar and i subbed 4
 but answer was sub in 5 LOLOL
only marks i lost
there goes a perfect score fml

Ouch. >.<

Don't worry, it's only 1 mark lost in a SAC.. you can still get 50 if you score perfect (or lost 1 mark) in the exams. And it also depends on your cohort.

[superstar1]

Do you have to get hundreds in all your Sacs to be able to get 50 in your study score.

[mojomojo]

Do you have to get hundreds in all your Sacs to be able to get 50 in your study score.

Nah, it depends on your cohort.

Just estimate how many students (including youself) in your class(es) are gonna get perfect mark in both exams (or -1 mark), and if your ranking is within that range, you should be fine in getting a 50 if you ace the exams as well.