Let the roots be alpha[α] and 3alpha[α]

=> α+3α = -b/a

=> 4α = -b/a

=> α = -b/4a ------(1)

=> α×3α = c/a

=> 3(α)^2 = c/a -----(2)

substitute (1) in (2)

=> 3(-b/4a)^2 = c/a

=> b^2/16a^2 = c/3a

=> b^2 = (16a^2*c)/3a

=> b^2 = 16ac/3

=> 3b^2 = 16ac

=> b^2 = 16ac/3  

=> b^2/ac   = 16/3

=>b^2:ac   = 16:3

ANS =[c]

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