Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 Help Me ! » Sets, Functions, Injunctions and Bijunctions » 2007-02-07 22:18:01

Replies: 1

I have been given this question to answer as either integer numbers or formulas...

Given two sets A and B with |A| = 9 and |B| = 17.

1. What is the number of functions from A to B?

2. What is the number of injective (one-to-one) functions from A to B?

3. What is the number of bijective (one-to-one and onto) functions from A to A?

Any explanations and help would be much appreciated. Thanks!

#2 Help Me ! » Cartesian Product » 2007-02-07 22:12:11

Replies: 1

Can anybody help me with cartesian products? I have a question I need help doing...

if A = {a9,a6,a2,a10}, B={a6,a9}, and C={a6,a7}, determine:

1. A  ×  B  =

2. the set (A $B)  ×  C

Note: $B = OR

Cheers smile

#3 Re: Help Me ! » Greatest Common Divisor » 2006-11-29 02:48:23

Ah I understand now! Thanks for the explanation big_smile

#4 Help Me ! » Greatest Common Divisor » 2006-11-29 00:53:11

Replies: 3

What is, and how do I find, the greatest common divisor of 771,708 ?

#5 Re: Help Me ! » Find the median » 2006-11-15 02:53:38

ah, nice and simple then. Thanks for that! smile

#6 Help Me ! » 2 Tricky Probability Questions » 2006-11-15 02:24:52

Replies: 1

A salesman works for 236 days of the year and makes 8 calls each working day.
Moreover on average he has a 20 percent chance of making a sale on each call.

1. What is the probability that he makes no sales at all on a given day?

2. On about how many days will he make no sales at all?

Help would be brilliant! I don't know where to even start on this problem.

#7 Help Me ! » binomial function » 2006-11-15 02:04:08

Replies: 1

Another one I'm struggling with...

A group of 18 students is composed of 7 Chinese, 5 British and 6 Indian students. None of these students has multiple citizenship.

In your answer to the following question you may use the function binomial. The binomial coefficient,

which denotes the number of ways of selecting k objects out of n, is input as binomial(n,k)

What is the probability of selecting 2 Chinese students from this group?

It's hurting my brain. How do I work that out?? smile

#8 Help Me ! » Find the median » 2006-11-15 01:23:53

Replies: 2


I have a few questions to complete.
HEre is one of them...

If D  =  [20,9,100,38,16,31,73,97,42,39,99,90,74,22,95,48,94,20,89,26]

What is the median of the data in D?

Your answers must be numerical (e.g. 1.5, (5+3)/2, etc.)

Help with the answer and how I go about working these sorts of questions out would be amazing.

#9 Re: Help Me ! » Logic gates and boolean algebra » 2006-04-30 01:05:32

Hey guys,

In reply to John E. Franklin's question... I was taught to do karanugh maps with A on the left edge and B and C on the top edge with, like you say, 0 and 1 down and 00 01 11 10 across the top.

Thanks a lot for all your replies. They have certainly improved my understanding of the subject and have taken off a stress that I am suffering about the upcoming exam on it.

And Ricky, that piece of freeware is awesome! Thanks tons for that.


#10 Re: Help Me ! » Logic gates and boolean algebra » 2006-04-29 04:47:41

yes,  that line you thought was invalid does branch out from B. Sorry, my fault for forgetting to pu the dot to represent the split in.

#11 Help Me ! » Logic gates and boolean algebra » 2006-04-29 04:14:45

Replies: 10

Logoc gates, boolean algebra, truth tables, karnaugh maps... this stuff just doesn't click for me at all. So if anyone hear understands it, help would be muchly appreciated.
Here is the circuit... sorry it looks like a little kids drawing. i had to draw it in paint as i have no scanner to scan the official question paper with.

What I have to do is...

1. Determine the Boolean function implemented by this circuit. Express that you determine it from the circuit above.

2. Create a truth table for this circuit.

3. Simplify the Boolean function found from above (you may use karnaugh mapping or algebraic methods to simplify the expression)

4. Draw a simpler circuit.

Thats it. Any answer or absolutely any tips or whatever will be awesome!
cheers guys

#12 Re: Help Me ! » Hows about a little help here » 2005-12-31 12:24:09

Thanks for the help guys. As for the first question, "Nil" is an actual fault so must be counted.

#13 Help Me ! » Hows about a little help here » 2005-12-31 04:25:17

Replies: 4

Hey guys,
Got a few questions here. I know they are probably no more than GCSE standard but still, I need and appreciate the help.

The scenario is I work for a computer repair company.

1. During January, the following faults were recorded

Number    Fault
100           Hard Disk Drive
300           Power Supply
150           Operating System
200           Video Card
180           Wiring
30               Nil

Express each fault occurrence as a percentage of the total number of faults.

2. During the year the following numbers of computers were received for repair

Jan - 960
Feb - 900
Mar - 800
Apr - 750
May - 600
Jun - 650
Jul - 600
Aug - 400
Sep - 600
Oct - 800
Nov - 200
Dec - 150

1.    What is the total number of computers received for repair?
2.    What is the mean number received per month?
3.    What is the median of the data above?
4.    What is the mode of the data above?

Thanks for your time.

#14 Help Me ! » More questions from me... » 2005-11-24 02:04:35

Replies: 2

A few more bugging questions from my maths mod....
It isn't so much the answers (I can do them on a calculator easily), I have to show the method of working them.
Answers and/or method of working out for any of these would be much appreciated smile

1. Express 5.678 x 10³ as a whole number i.e without the index.

2. Calculate 2 x 10³ x 3 x 10³. Express the answer both as a whole number and by using indices.

3. What is 250/10 in hexadecimal?

4. A computer is advertised for sale at £5000 plus VAT at 17.5%. What is the total price payable?

5. A computer monitor is advertised as "25% off, price now £187.50". What was the price before the discount?

6. A lottery win of £100,000 is to be divided amongst 4 players who have won the following shares in the syndicate. Adam 5; Brenda 8; Charlie 3; Diana 4. How much does each player get?

7. An Ordinance Survey map is printed at a scale of 1:25000. A walker measures a distance between two points on the map and finds that it is 225mm. What is the actual distance across the ground? Give your answer using a suitable unit of measure.

#15 Re: Help Me ! » Hello there. Anyone help me? » 2005-11-24 00:22:42

That's awesome. Thanks a lot for that speedy reply. Don't worry about that binary question. I think i sussed it. smile

#16 Help Me ! » Hello there. Anyone help me? » 2005-11-23 23:52:04

Replies: 3

Hey, I study computing and have a small Math module to do over the weekend. (The most feared unit on all my course for me as I never have had a good mind for maths.

Anyway, here are some questions that are bugging me...
Could anyone please tell me either the answers and/or the steps of working them out?

1. (Please note the cubed symbols have minus' before them in this one) Calculate 2 x 10-³ x 3 x 10-³

2. Binary to denary conversion. Convert 11111110 divided by 2

3. Calculate: 22 1/3rd
                   3 3/8ths

4. Calculate 22 1/3 -  3 3/8

5. (22 1/3 / 3 3/8) + 22 1/3

Thanks for taking time to help smile

Board footer

Powered by FluxBB