Help with nth term and number sequence

11 Plus Maths – Preparation and Information

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exam2019
Posts: 227
Joined: Fri Sep 29, 2017 3:14 pm

Help with nth term and number sequence

Post by exam2019 »

Hi

Can anyone advise on the best way to tackle the following questions?

a. 3 5 7 9 11 13. nth term = ?

b. 7 11 15 19 23 27. nth term = ?

The answers are:
a. 2n+1
b. 4n+3

Any suggestions on how to approach these sorts of questions? Or online resources to teach DD how to approach them?

Thanks!
delian
Posts: 2
Joined: Tue Dec 29, 2020 10:32 am

Re: Help with nth term and number sequence

Post by delian »

exam2019 wrote:Hi
a. 3 5 7 9 11 13. nth term = ?
The generic formula is an+b
The step between the prev and next numbers is 2, that means a=2, i.e. 2n+b
Then you can figure out the value of b:
2n+b=3, where n=1
exam2019
Posts: 227
Joined: Fri Sep 29, 2017 3:14 pm

Re: Help with nth term and number sequence

Post by exam2019 »

Thank you!
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