Question

The sum of how many terms of the A.P. 10, 12., 14, will be 190

Answer 1

an=190

d=2

n=?

a=10

an=a+(n-1)d

190=10+(n-1)2

t.p

190-10=(n-1)2

180=(n-1)2

180/2=(n-1)

90=(n-1)

t.p

n=90-1

n=89

answer is n=89

I hope this is useful