Question

the sum of how many terms of the arithmetic progression 10 12 14 will be 190​

Answer 1

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

190=n/2 (2x10+(n-1)2

190=n/2 (20+2n-2)

190=n/2(18+2n)

380=18n+2n^2

2n^2+18n-380

n^2+9n-190

solving the equation by quadratic formula

n=10

this is the answer