Let, present age of Mukesh and Sailee are x and y years respectively. Five years earlier, x–5=7(y–5) ⇒x–7y=–30....(i) After 15 years, x+15=3(y+15) ⇒x–3y=30...(ii) From (i) and (ii), we have, x=5y ∴ x = 75, y = 15 Then x+y=75+15=90 years