Age of father =7x Age of son = 3x Calculation: According to the given condition, we can set up an equation: (7x)×(3x)=756 ⇒21x2=756 ⇒x2=756÷21 ⇒x2=36 ⇒x=6 Now, we find their current ages: Father's current age =7x=7×6=42 years Son's current age =3x=3×6=18 years Next, we find their ages after 6 years: Father's age after 6 years =42+6=48 years Son's age after 6 years =18+6=24 years Finally, we find the ratio of their ages after 6 years: Ratio =48:24 ⇒ Ratio =2:1