susan was 20 years old when her daughter janet was born. what will Janet's age be when their age ratio is 7:2
To find out Janet's age when the age ratio between Susan and Janet is 7:2, we first need to determine the current age of Susan. Since the information states that Susan was 20 years old when Janet was born, we can calculate Susan's current age by adding the age difference to Janet's age.
Let's assume the current age of Janet is J years, and Susan's age is S years. Given that the age difference between them is always constant, the equation would be:
S = J + 20
Next, we can express the age ratio of 7:2 as a mathematical equation:
S / J = 7/2
By substituting the value of S from the first equation into the second equation, we can solve for J:
(J + 20) / J = 7/2
To remove the denominators, we can cross-multiply:
2(J + 20) = 7J
Simplifying the equation:
2J + 40 = 7J
Rearranging the equation:
5J = 40
Dividing both sides by 5:
J = 8
Therefore, Janet's current age is 8 years old.