Question

Find the value of x when ap given below 2+6+10+..... +x=1800

Answer 1

an= 1800. a=2 d=4 n=x

an=a+(n-1)d

1800=2+(x-1)4

1800-2=(x-1)4

1798/4=x-1

449.5+1=x

450.5=x (approx)

I guess not sure