Father – 6 = Sister – 6 + Brother – 6 + 14
Father = sister + brother + 8…. (1)
Statement I.
Farther = Roma + 20
Roma = 7/6 x brother
This statement alone is not sufficient to answer
Statement II.
Brother – 4 = 5/3 x (Sister - 4)
3 x brother – 12 = 5 x sister – 20
3 x brother – 5 x sister = - 8……….. (2)
This statement alone is not sufficient to answer the question
Statement III.
Father – 8 = Sister – 8 + Brother – 8
Father = brother + Sister – 8….. (3)
On combining I and II
Father = sister + brother + 8 ……. (1)
Also, Father = Roma + 20
Roma = 7/6 x brother
So, 7/6 x brother + 20= brother + sister + 8
6x sister – Brother = 72…………… (4)
Also, 3 x brother – 5 x sister = - 8 …..(2)
On solving 4 and 2, we get
Sister = 16 years
Age of sister after 12 years = 16 + 12 = 28 years
This combination is sufficient to answer the question.
Statement III have same information what we have in question initially.
So, combination of statement III with any other statement is not sufficient.
So only (I and II) is sufficient to answer the question.
Hence answer is option A