On the occasion of birthday of Mrs. Paul's daughter, Mrs. Paul told her daughter, "4x years ago, I was 4 times your age and my age was 2 times your age 2x years ago." Which of the following can be the age of Mrs. Paul at present, if the difference in the present ages of mother and daughter is 18?

Let M and D be present ages. M - D = 18. From the first condition: M - 4x = 4(D - 4x) which simplifies to M = 4D - 12x. From the second: M - 2x = 2(D - 2x) which simplifies to M = 2D - 2x. Equating the two expressions for M: 4D - 12x = 2D - 2x, so 2D = 10x or D = 5x. Substituting into M - D = 18 gives M - 5x = 18. Since M = 2D - 2x = 2(5x) - 2x = 8x, we have 8x - 5x = 18, so 3x = 18, x = 6. Thus M = 8(6) = 48.