If the sum of the first n terms in the arithmetic sequence (an) is Sn and S3 = 8 and S8 = 42 are known, then the value of A8 is A: 16 B: 18 C: 20 D: 22 is the question wrong?

If the sum of the first n terms in the arithmetic sequence (an) is Sn and S3 = 8 and S8 = 42 are known, then the value of A8 is A: 16 B: 18 C: 20 D: 22 is the question wrong?

s3=na1+n(n-1)d=3a1+3d=8
s8=8a1+28d=42
a1=49/30
d=31/30
a8=a1+7d=49/30+7*31/30=266/30=133/15