Question

sum of the 5th and 10th terms of an arithmetic sequence which are equal to the 20th term (80). find the 30th term

Answer 1

Yo sup??

a5=a+4d

a10=a+9d

a20=80=a+19d

a+4d+a+9d=a+19d

a=6d

80=6d+19d

80=25d

d=3.2

a=19.2

a30=a+29d

=19.2+92.8

=112

Hope this helps.