Question

in the sequence a1 , a2 , ....., a n the sum of any three consecutive terms is 40. if the third term is 10 and the eight term in 8 then the 1000th term is

Answer 1

a+2d=10
a+7d=8
subtracting
5d=-2
d= -2/5
a=54/5
1000th term=54/5+999×(-2/8)