Question

find the number of term AP 3,10/3.11/3, so that the sum is 23​

Answer 1

Answer:

let no of term =x

d=10/3-3

=1/3

Sn=n/2{2a+(n-1)d}

23 =n/2{2×3+(n-1)1/3}

23=n/2{6+n/3-1/3}

23=n/2{17+n}/3

23×6=17n+n^2

n^2+(23-6)n-138=0

n^2+23n-6n-138=0

n(n+23)-6(n+23)=0

(n+23)(n-6)=0

so

n-6=0

n=6 Ans