Answer: Alvin = 42 yrs , Elga = 21 yrs
Explanation:
Let Elga's age be x , and Alvin's age be y ,since Alvin is two times Elga's age , then
Alvin's age = 2x , that is
y = 2x ............... equation 1
The sum of their ages is 63 implies
x + y = 63 .............. equation 2
Solving the resulting linear equations by substitution method.
Substitute equation 1 into equation 2 , we have
x + 2x = 63
3x = 63
x = 63/3
x = 21
Therefore : Elga is 21 years old , then Alvin will be 21 x 2, which will be 42