Let the age of one friend = x years
Age of the other friend = 20 - x years
Four years ago,
Age of one friend = (x - 4) years
Age of the other friend = (20 - x - 4) years
According to the condition, (x - 4)(16 - x) = 48
⇒16x−64−x2+4x=48
⇒−x2+20x−64−48=0
⇒−x2+20x−112=0
⇒x2−20x+112=0
Comparing the given equation to the standard form, we get, a = 1, b = -20, c = 112
∴b2−4ac=(−20)2−4(1)(112)=400−448=−48<0
Since b2−4ac<0, the quadratic equation has no real roots.
∴ The given situation is not possible