Question

If in an A.P. ratio of fourth term and 9th term is 1: 3 find
the ratio of 12th term and 5th term.​

Answer 1

Answer:

RATIO = 3:1

Step-by-step explanation:

⇒ TERM 4÷TERM 9 = 1 ÷3

⇒   a+(4-1)d÷a+(9-1)d = a+3d ÷ a+8d = 1÷3

⇒   (a+3d)3 =(a+8d)1

⇒    3a+9d = a+8d

         ∴ d = -2a

⇒NOW,

    TERM 12÷TERM 5 = a+(12-1)d÷a+(5-1)d

                                   = a+11d ÷ a+4d

                                   = a+11(-2a) ÷ a+4(-2a)

                                   = a-22a ÷ a-8a

                                   = -21a ÷ -7a

                                   =  -3 ÷ -1

                                   =   3 ÷ 1

                                   ∴ ratio is  3 is to 1

         MARK IT AS BRAINLIEST PLEASE ........

Answer 2

Answer:

refers to the attachment