• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Mathematics: Post your doubts here!

Messages
94
Reaction score
66
Points
28
ii) split into 2 cases
1. Thousand digit is 3
1st digit: 1 choice (can only be 3)
4th digit: 2 choices ( can only be 4 or 8)
2nd digit: 5 choices(any of the remaining)
3rd digit: 4 choices(any of the remaining)
2. Thousand digit is 4
1st digit: 1 choice (only 4)
4th digit 1 choice (only 8)
2nd digit: 5 choices
3rd digit: 4 choices
Total = (2*5*4) + (5*4)

iii) Split into 3 cases:
1. 1 digit number: 1 choice (5 only)

2. 2 digit number:
2nd digit: 1 choice ( 5 only)
1st digit: 7 choices

3. 3 digit number
3rd digit: 1 choice
1st and 2nd digit: 7 choices each
Total = 1 + 7 + (7*7)
thanks alot!
 
Messages
94
Reaction score
66
Points
28
(ii) All numbers must start with either 3 or 4 to be between 3000 and 5000 and end with 4 or 8 to be even numbers.
They can be like 3__4, 3__8 or 4__8. Cannot be 4__4 as digits aren't repeated.
Total available digits are 7 so remaining for the middle two digits are 5. There are 2 spaces so 5P2. This will be thrice as there are 3 combinations for first and last digits. Hence total numbers that can be made are 5P2*3=60.

(iii) Numbers can be 1-digit, 2-digit and 3-digit. All numbers must have 5 as last digit to be a multiple of 5 as 0 is not available. So there will be 1 1-digit number. 7 2-digit numbers as first digit of these numbers can be any one of the seven available digits as digits can be repeated so they will be 35, 45 etc. There will be 49 3-digit numbers as both first and second digits can be any of the seven available digits. These will be 485, 145 etc. Total are 1+7+49=57.
thanks alot!
 
Messages
237
Reaction score
41
Points
38
hey does anyone know any tips for the actual exam? like how to check your answers to make sure youre going in the right direction and such?
 
Messages
237
Reaction score
41
Points
38
Someone help me with this S1 problem. It's from O/N/13 - 61. I solved it (attached the picture) - my distribution for X is wrong; can someone please explain why the distribution for X is lower than that for Y? I attached the markscheme screenshot too, haha. Please help!
View attachment 52744
View attachment 52746
youre 3 standard deviations below and above the mean. so 3 x sqr rt of 49 below and above, so 21 below 30 and 21 above 30 and so from 9 to 51
 
Messages
304
Reaction score
193
Points
53
hey does anyone know any tips for the actual exam? like how to check your answers to make sure youre going in the right direction and such?
Are you asking about P3 or S1?
In P3 it is better just to review your answer and then proceed to the next.If you start checking whether your answer is correct it will take a lot of time and cause trouble later.Just review the working for any careless errors.In the end if you have time go through all the answers again,especially those you have your doubts on.In p3 it will be better to solve the easier questions first;those you're well acquainted with.

In S1,leave permutation and combination for the last.You should attempt other questions in order.I don't think there is any way to check your answers except for in normal distribution where you can check the probability by reversing.Again,it would be helpful to check in the end if time permits.

Try not to confuse yourself about a particular solution.There are times when you think what you've done is wrong although it's correct.
 
Messages
6,514
Reaction score
26,001
Points
698
Are you asking about P3 or S1?
In P3 it is better just to review your answer and then proceed to the next.If you start checking whether your answer is correct it will take a lot of time and cause trouble later.Just review the working for any careless errors.In the end if you have time go through all the answers again,especially those you have your doubts on.In p3 it will be better to solve the easier questions first;those you're well acquainted with.

In S1,leave permutation and combination for the last.You should attempt other questions in order.I don't think there is any way to check your answers except for in normal distribution where you can check the probability by reversing.Again,it would be helpful to check in the end if time permits.

Try not to confuse yourself about a particular solution.There are times when you think what you've done is wrong although it's correct.
what abt s2?
 
Messages
2,206
Reaction score
2,824
Points
273
Thanks,after seeing that somehow i got 6/9 in one :)
The videos there are for clearing your basics and trick to crack tricky question patterns. Rest it depends on your knowledge of mathematics how you take the question. Keep practicing. You will score 9 on 9 easily in few days. ^_^
Good luck.
 
Messages
16
Reaction score
10
Points
13
Hey!! Can someone help me with Q10 , (b) (ii) please
 

Attachments

  • P_20150518_190733.jpg
    P_20150518_190733.jpg
    1 MB · Views: 11
  • P_20150518_190725.jpg
    P_20150518_190725.jpg
    1,006 KB · Views: 9
Messages
18
Reaction score
19
Points
13
hi can someone help me
when can i use ln while integrating?
how can i calculate the greatest value and least value of argument?
how can i expand (1+x)(2+2x)^-1
 
Messages
237
Reaction score
41
Points
38
Are you asking about P3 or S1?
In P3 it is better just to review your answer and then proceed to the next.If you start checking whether your answer is correct it will take a lot of time and cause trouble later.Just review the working for any careless errors.In the end if you have time go through all the answers again,especially those you have your doubts on.In p3 it will be better to solve the easier questions first;those you're well acquainted with.

In S1,leave permutation and combination for the last.You should attempt other questions in order.I don't think there is any way to check your answers except for in normal distribution where you can check the probability by reversing.Again,it would be helpful to check in the end if time permits.

Try not to confuse yourself about a particular solution.There are times when you think what you've done is wrong although it's correct.

You can check your normal distribution answers with your calculator. Just go mode>stat>AC then shift 1>Dist>P(
enter your values any it does it for you. I use it in case I get the wrong values from the table. And thanks for your help anyway.
 
Top