(d) 9 years
Mr. Manoj's age be (10x + y) yrs.
Then, his wife's age = (10y + x) years
Given,
\(\frac{1}{11}\)(10x + y + 10y + x) = (10x + y) – (10y + x)
\(\Rightarrow\)\(\frac{1}{11}\)(11x +11y) = 9x -9y
\(\Rightarrow\)x + y = 9x – 9y
\(\Rightarrow\)8x = 10y
\(\Rightarrow\)\(\frac{X}{y}\) = \(\frac{5}{4}\)
\(\therefore\) x = 5, y = 4 (because any other multiple of 5 will make x two digits)
\(\therefore\) Difference = 9x – 9y = 9 (x – y) = 9 (5 – 4) = 9 yrs.