general
Maths Puzzle
if 6 times the sixth term is equal to 15 times the fifteenth term ,find its 21st term
Read Solution (Total 2)
-
- 0 If AP is considered.
nth term = a+(n-1)*d
6(a+5d) = 15(a+14d)
6a + 30d = 15a + 210d
9a = -180d
a = -20d
a + 20d = 0 which is equal to 21st term. - 12 years agoHelpfull: Yes(4) No(0)
- Is it case of AP or GP?
- 12 years agoHelpfull: Yes(0) No(0)
general Other Question