## Bdmo National2014: junior 5

- atiab jobayer
**Posts:**23**Joined:**Thu Dec 19, 2013 7:40 pm

### Bdmo National2014: junior 5

A new is to be formed by removing some terms from the series 1,2,3,4..............,30 such that no term of the new series is obtained if any term of the new series is doubled. Maximum how many terms can there in new series?

math champion

### Re: Bdmo National2014: junior 5

First of all, there are a few minor typos.

Here's a possible approach.

The statement, I guess, should be "A new series is to be formed by removing some terms from the series $1,2,3,4..............,30$ such that no term of the new series is obtained if any term of the new series is doubled. Maximum how many terms can there be in the new series?"atiab jobayer wrote:A new is to be formed by removing some terms from the series 1,2,3,4..............,30 such that no term of the new series is obtained if any term of the new series is doubled. Maximum how many terms can there in new series?

Here's a possible approach.

Please

**Install $L^AT_EX$ fonts**in your PC for better looking equations,**Learn****how to write equations**, and**don't forget**to read**Forum Guide and Rules.****"When you have eliminated the impossible, whatever remains, however improbable, must be the truth." - Sherlock Holmes**- atiab jobayer
**Posts:**23**Joined:**Thu Dec 19, 2013 7:40 pm

### Re: Bdmo National2014: junior 5

Yes. I've made a solution. I agree with Labib.In the new series, there must be contain 20 term. The missing numbers are : 2,6,8,10,14,18,22,24,26,30.

math champion