Question

( theta quad a=3 quad, d=7 cdot quad a_{n}=171 )
( Rightarrow ) we thow ( a_{n}=a+(n-1) d )
[
171=3+(n-1) 7
]
?
( =25 )
( -sin =frac{25}{2} times(6+24 times 7) Rightarrow frac{25 times 194}{2} )
72175

# & A.P. x 3,10,17,24 -.-- 171. find sum of Is A.P.

Solution