Question

sum of 15 terms of an AP is 600, and the common difference is 5 .find the first term

Answer 1

HELLO FRIEND ♥️ HERE IS UR ANSWER ♥️

Given n=15, S15=600, d=5

We know that 
Sn=n2[2a+(n−1)d]


⇒S15=152[2a+(15−1)5]=152[2a+(14)5]=15(a+35)

⇒600=15(a+35)⇒60015=a+35⇒40=a+35⇒a=


40−35=5

Hence first term=5

$hope \: helps$