(i) Let the fraction be x/y

According to the given conditions

(ii) Let the present age of Nuri be x (in years) and Present age of Sonu be y (in years)

According to the given conditions,

Hence, Present age of Nuri is 50 years and present age of Sonu is 20 years

(iii) Let x be the digit at unit's place and y be the digit at ten's place.

According to the given condition