Number series

Advice on 11 Plus VR papers and problems

Moderators: Section Moderators, Forum Moderators

Post Reply
wellprepared
Posts: 67
Joined: Tue Sep 27, 2011 2:21 pm

Number series

Post by wellprepared »

Hello,
My dd came across one of the number series
11 14 22 16 __ __
It is standard format paper so there is no possibility of looking in multiple options.
she thinks it is two series running together with the answers being 44 and 18
11 22 44.........double the previous number
14 16 18.........+4 to previous number
But the answer is 33 and 18
my trouble is there no reason for the answer not to be 44 with her explanation.....
she says to prove it to bee 33 they should give series a bit longer to be obvious that it is 11 times table....
Do these unclear questions appear in actual test and if they do both the answers are considered correct?
Please help....
Sally-Anne
Posts: 9235
Joined: Wed Jan 11, 2006 8:10 pm
Location: Buckinghamshire

Re: Number series

Post by Sally-Anne »

It is an ambiguous question. The real tests (depending upon the school/area) are usually very carefully proof-read to iron out any ambiguities like this. I can only recall one occasion when an error was identified on a real paper - a few years ago in Herts.
Manny0311
Posts: 125
Joined: Mon Apr 09, 2012 8:56 am

Re: Number series

Post by Manny0311 »

hello all

How do you know which sequence to use on these sort of questions.?

22, 21, 23, 23, 24, 25, 25 (....)

The way I look into this is that you can go both ways...22 to 23, 23 to 24, 24 to 25

Alternatively, use 21 instead but then it jumps by 2..21 to 23, 23 to 25 and so on

Answer is 27 but why ??

Also I have one more:-

93, 92, 95, 95, 97, 98 (...)

Answer is 99 but why?

Many Thanks !
faitaccompli
Posts: 357
Joined: Mon Dec 05, 2011 6:44 pm

Re: Number series

Post by faitaccompli »

22 21 23 23 24 25 25

every other number ncreasing by one

22 23 24 25

every other number increasing by two

21 23 25 27
faitaccompli
Posts: 357
Joined: Mon Dec 05, 2011 6:44 pm

Re: Number series

Post by faitaccompli »

93 92 95 95 97 98

93 95 97 ... 99

every other number increasing by two

92 95 98

every other number increasing by three
Manny0311
Posts: 125
Joined: Mon Apr 09, 2012 8:56 am

Re: Number series

Post by Manny0311 »

faitaccompli wrote:93 92 95 95 97 98

93 95 97 ... 99

every other number increasing by two

92 95 98

every other number increasing by three
So surely answer could be 99 or 101...how do you know which one to use or am i having a blond moment here ?
faitaccompli
Posts: 357
Joined: Mon Dec 05, 2011 6:44 pm

Re: Number series

Post by faitaccompli »

Because it is in sequence - so it needs to match the penultimate number in the list.

ie.

93 92 95 95 97 98 99
Manny0311
Posts: 125
Joined: Mon Apr 09, 2012 8:56 am

Re: Number series

Post by Manny0311 »

faitaccompli wrote:Because it is in sequence - so it needs to match the penultimate number in the list.

ie.

93 92 95 95 97 98 99
ok, but then both sequences would give you 101 not 99 and the answer is 99 on the answers ??
faitaccompli
Posts: 357
Joined: Mon Dec 05, 2011 6:44 pm

Re: Number series

Post by faitaccompli »

Manny0311 wrote:
faitaccompli wrote:Because it is in sequence - so it needs to match the penultimate number in the list.

ie.

93 92 95 95 97 98 99
ok, but then both sequences would give you 101 not 99 and the answer is 99 on the answers ??

The number in bold and underscored is the missing number! so the original sequence was

93, 92, 95, 95, 97, 98, ?
Orson
Posts: 238
Joined: Sun Jan 13, 2008 7:18 pm
Location: Gloucestershire

Re: Number series

Post by Orson »

Going backwards from the question mark every other number goes down by 2, i.e. 97, 95, 93, ... So the preceding number (the question mark) was 99.
The number after 99 would be 101 because every other number preceding it goes up by 3, i.e. 92, 95, 98, ... However, you are not required to give this number.
Post Reply
11 Plus Mocks - Practise the real exam experience - Book Now