Answer:
Zyndy is 14, Vyndel is 7.
Explanation:
Let Zyndy's age be represented by 'z', and Vyndel's age be represented by 'v'.
Zyndy is twice the age of Vyndel, so z=2v
The sum of their age is twenty-one, so z+v=21
Sub the first equation above into the second to get:
2v+v=21
3v=21
v=7
Knowing v=7, we can say z=2(v)=14.