Question 354971

asubn = asub1 + (n-1)d
asub(n+1) = asub1 + nd.
Adding corresponding sides,
asubn + asub(n+1) = 2asub1 + (2n-1)d.
then
299 = 2asub1 + (2n-1)d
299 = 2*(1) + (2n-1)*3
299 = 2 + (2n-1)3
297 = (2n-1)3
99 = 2n-1
100 = 2n
n = 50.
so its the 50th term (148) and the 51st term (151).