The fourth term of an Ap is 10. If eleventh term is one more three times of the fourth term find the sum of its 25 terms
Answers
Answered by
7
Sum of 25 terms = 2000
t 4. =. 10
t 11. =. 3 × 10 + 1
= 31
d. = 31 - 10 / 3
= 7
t 1. = 10 - (2×7)
= 10 - 14
=. -4
t 25.= t1 + 24 d
= -4 + 168
=. 164
Sn. =. 25 / 2 ( -4 + 164)
= (25 × 160 ) / 2.
= 2000
Similar questions