Let the ages of Ram, Rahim and Ramesh be $$x,y,z$$ respectively. Average age of Ram and Rahim = 18 years => $$frac{x+y}{2}=18$$ => $$x+y=18 imes2=36$$ -----------(i) Similarly, $$y+z=25 imes2=50$$ --------------(ii) and $$x+z=29 imes2=58$$ --------------(iii) Adding equations (i),(ii) and (iii) => $$2(x+y+z)=36+50+58=144$$ => $$x+y+z=frac{144}{2}=72$$ Substituting value from equation (i) in above equation, we get : => $$z=72-36=36$$ years Similarly, $$x=22$$ years and $$y=14$$ years $$ herefore$$ Age of the eldest of the three = 36 years => Ans - (D)