The ratio of a man's age to his father's age is 4 : 5, and the ratio of his age to his son's age is 6 : 1. Four years ago these ratios were 11 : 14 and 11 : 1, respectively. The ratio of the age of the grandfather to that of the grandson 12 years from now will be:

Answer: Option C

Solution

Answer: Option C

Solution:

$$\begin{array}{rl}& 1\text{ unit}\to 4\text{ years}\\ & \text{So current age}\\ & \text{Man}:\text{Father}:\text{Son}\\ & \text{48}\text{60}\text{8}\\ & \text{Required answer}=\frac{60+12}{8+12}\\ & =\frac{72}{20}\\ & =\frac{18}{5}\text{ or }18:5\end{array}$$