If 30% of (B-A) - 18% of (B+A) = 0, then the ratio of A:B is equal to:

30% (B-A) - 18% (B+A) = 0

30% (B-A) = 18% (B+A)

\(\frac{B+A}{B-A}\) = \(\frac{5}{3}\)

 here

B + A = 5 ---- (i)

B - A = 3 ----- (ii)

   2B = 8               (after adding)

     B = 4        ------ Putting in equation (i) 

⇒ 4 + A = 5

⇒ A = 1

⇒ A    :    B = 1    :    4