Answer:
[tex]\boxed{\pink{\tt \leadsto Sum \ of \ first \ five \ terms \ is \ 50 . }}[/tex]
Step-by-step explanation:
Given that , the sum of the first nine terms of an arithmetic series is 162 and the sum of the first 12 terms is 288.
[tex]\boxed{\red{\bf \bigg\lgroup For \ answer \ refer \ to \ attachment \bigg\rgroup }}[/tex]
• The sum of n terms of an AP is
[tex]\boxed{\orange{\sf S_n = \dfrac{n}{2}[2a+(n-1)d] }}[/tex]
• nth term of an AP is given by ,
[tex]\boxed{\blue{\sf T_n = a+(n-1)d }}[/tex]