Maths Problem

[Akazeem]

Concerned Parent,

We recently bought 11 Plus CD which proved very good for our child, however, when our child got to one of the questions she spent almost 6mins on it and still got that particular question wrong.

We would like anybody to help us with the simple logic for solving the question:

The question is as follow: 2 2 4 12 12 24 (?)
the answer given is 72

[helper]

you have to do x1, x2, x3, then again x1, x2, x3

so 2x1= 2
2x2=4
4x3=12

12x1=12,
12x2=24
24x3 =72


Trick with all these questions is to write above the sequence the operation needed to get between adjacent numbers. Then look for a pattern. Sometimes there may be two or more possibles e.g. an addition or a multiplication, but only one will fit a pattern.

Trouble with these things is they are always easy in retrospect.

hope that helps

[Mike Edwards]

Hi

The previous post is correct for most of the questions

However,

1 2 5 3 9 5 13 8

gives a patern of +1, +3, +2, +6, -4, +8, -5

This sequence is actually 2 sequences interlinked i.e.

1 5 9 13 increasing by 4 each time

and

2 3 5 8 increasing by 1, then 2, then 3

In the first instance where patterns are not obvious then look for interlinked patterns.


2 2 4 6 10 16 26

gives a pattern of

0 +2 +2 +4 +6 +10

This is a Fibonacci type question where the sum of the previous two numbers gives the next number.

It is worth teaching square number patterns

1 4 9 16 25 36 etc

and cubic number patterns

1 8 27 64 125

I dont think that a child should spend 6 minutes on any question. If she does not have the answer after 2 minutes she should be encouraged to move on. The CD will indicate which questions she did not get right or took a long time to complete. Then, as a parent tutor, it is your role to advise her on how to work it out.

Remember there is one important valid answer to any question that often gets overlooked that is "I don't know". There will always be people on this site who can offer advice.

Regards

Mike

[Tse]

My daughter has year 6 maths homework but we don't know how to do it. We need help.
The question is:
A computer checks e-mails and news updates on a regular basis. In a 24-hour period, the computer checks e-mails every five minutes and news updates every seven minutes. Neither work when both checks are being done a the same time and this causes an error message on the screen. There is one error message after an hour and three error messaages after two hours. How many error messages are there after 24 hours?
A 24 B 35 C 41 D 48 E 240

[jah]

The answer is C 41

5 and 7 are both prime numbers, so there will be an error message every 5x7=35 minutes.

(This fits in with the information given of 1 in 1 hour and 3 in 2 hours - 35 mins, 70 mins and 105 mins)

Number of minutes in 24 hours =24x60=1440


1440/35=41.143 to 3 decimal places.

Answer required is the whole number less than this i.e. 41

[Mindy]

Well done Jah.

I had my spreadsheet open trying to work this out when you had already done it.

We arrived at the same answer but your method is entirely logical and more elegant.

[sj355]

An alternative answer based on the X1 X2 X3 method also is that all three first numbers are multiplied by 6 and hence give us 12 12 24 and then these three numbers will aslo be multiplied by 6 to give us 72 72 144.

INEX




We would like anybody to help us with the simple logic for solving the question:

The question is as follow: 2 2 4 12 12 24 (?)
the answer given is 72[/quote]

[Tse]

Thank you very much, Jah.