Question

The sum of first six terms of an AP os 42. The ratio of it 10th term to its 30th term is 1:3. Find the first term of the AP

Answer 1

sn=n/2(2a+(n-1)×d..
using this formula
s6=6/2 (2a+5×d)
s6=3(2a+5d)
s6=6a+15d------------i)
then we have
a+9d/a+29=1/3
cross multiply the two we'll get
3(a+9d)=1(a+29d)
3a+27d=a+29d
2a=2d
a=d--------ii
putting i and ii
s6=6a+15a
s6=21a
42=21a
a=2

Answer 2

so ur the first term is 2 hope it helps uhh.... if uhh r satisfied thn plzzzzz mark as brainliest ans.....thank you