Joe`s age, Joe`s sister`s age and Joe`s fathers age sums up to a century. When son is as old as his
father, Joe`s sister will be twice as old as now. When Joe is as old as his father then his father is twice as old as when his sister was as old as her father.Age of her father ?
60
50
65
55
Explanation:
Joe + sister + father = 100
After x years let us consider Joe`s age is equal to his father
Joe + x = father
Therefore,
sister + x = 2 x sister
$\Rightarrow$ sister = x
Joe + sister = father
Therefore,
2 $\times$ father = 100
Hence, Father = 50
Joe + sister + father = 100
After x years let us consider Joe`s age is equal to his father
Joe + x = father
Therefore,
sister + x = 2 x sister
$\Rightarrow$ sister = x
Joe + sister = father
Therefore,
2 $\times$ father = 100
Hence, Father = 50