Let respective ages of Rustam, Preetam and Geetam be $$r,p,g$$ years Average age of Rustam and Preetam = 39 years => $$frac{r+p}{2}=39$$ => $$r+p=78$$ ----------(i) Similarly, $$p+g=56$$ ----------(iii) and $$r+g=68$$ ------------(iii) Adding all the equations, we get : => $$2(r+p+g)=78+56+68$$ => $$r+p+g=frac{202}{2}=101$$ ------------(iv) Substituting value from equation (i) in equation (iv), => $$78+g=101$$ => $$g=101-78=23$$ years Similarly, $$r=45$$ years and $$p=33$$ years $$ herefore$$ Age (in years) of the youngest, i.e. Gautam after 10 years = $$23+10=33$$ years => Ans - (C)