If 18th and 11th term of an A.P. are in the ratio 3 : 2, then its 21st and 5th terms are in the ratio

As 18th term : 11th term ratio is 3:2


18th term is a + 17d and 11th term is a + 10d



3a + 30d = 2a + 34d


a=4d…………….(1)


21st term is a + 20d = 24d (putting value of a from (1))


And 5th term is a + 4d= 8d (putting value of a from (1))


Ratio of 21st term : 5th term is


= 3:1

35