## BdMO 2020 Preliminary Higher Secondary P4

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mdvirus
Posts:1
Joined:Sat Feb 20, 2021 7:13 pm
BdMO 2020 Preliminary Higher Secondary P4
If \$n\$ is even, then \$T(n) = T(n - 1) + 1\$ and if \$n\$ is odd then \$T(n) = T(n - 2) + 2\$. If \$T(1) = 7\$ what is \$T(2020)\$?

Asif Hossain
Posts:193
Joined:Sat Jan 02, 2021 9:28 pm

### Re: BdMO 2020 Preliminary Higher Secondary P4

You should have posted the problem in BdMO problem section but anyways
If \$n+1\$ is odd then \$T(n+1)=T(n-1)+2 \Rightarrow T(n+1)=T(n)-1+2 \Rightarrow T(n+1)=T(n)+1\$
If \$n+1\$ is even then \$T(n+1)=T(n)+1\$ so \$T(n)\$ is in arithmetic progression so \$T(2020)=T(1)+(2020-1)=2026\$
Hmm..Hammer...Treat everything as nail

niamul21
Posts:1
Joined:Thu Jun 17, 2021 8:19 am

### Re: BdMO 2020 Preliminary Higher Secondary P4

mdvirus wrote:
Thu Apr 08, 2021 5:50 pm
If \$n\$ is even, then \$T(n) = T(n - 1) + 1\$ and if \$n\$ is odd then \$T(n) = T(n - 2) + 2\$. If \$T(1) = 7\$ what is \$T(2020)\$?
You did it right. Thanks