The sum of first and 5th term of an ascending ap is 26 and product of 2nd and 4th term is 160. Find sum of first 7 terms of a.p
Answers
Answered by
2
a+a+4d=26
a+2d=13
a=13-2d equa1
(a+d)*(a+3d)=160 equa2
(13-2d+d)*(13- 2d + 3d ) =160
(13-d) * (13+d)=160
169-d^ 2 = 160
d=3
- putting in equa 1
a = 13- 2 (3)
a= 13-6
a=7
- sum of first 7 terms
S7 = n/2{2a+ (n-1) d}
=> 7/2(14 + 6(3))
=> 3.5(32)
=>112 answer
Similar questions
English,
7 months ago
Social Sciences,
7 months ago
Hindi,
7 months ago
English,
1 year ago
Computer Science,
1 year ago
Social Sciences,
1 year ago
Math,
1 year ago