Answer:
Jewel is 7 years old
John is 1 year old
Dave is 17 years old
Step-by-step explanation:
From the question we are told that:
Jewel age is [tex]J=7 years[/tex]
John age [tex]J'=(D-16)years[/tex]
Dave's age a Year ago
[tex]D-1=2(J-1+J'-1)[/tex]
So that Dave.s age this Year could be
[tex]D=2((J-1)+(J'-1))+1[/tex]
Simplifying Equation for Dave's age we have
[tex]D=2((7)-1+(D-16)-1)+1[/tex]
[tex]D=2(6+D-15)+1[/tex]
[tex]D=2(D-9)+1[/tex]
[tex]D=2D-18+1[/tex]
[tex]D=17 Years[/tex]
Dave is 17 years old
Therefore
Johns age is
[tex]J'=(D-16)[/tex]
[tex]J'=17-16[/tex]
[tex]J'=1year old[/tex]
John is 1 year old
