can u solve this questions.i don't know what to do.

Answer:
8
Step-by-step explanation:
average is calculated as
average = [tex]\frac{sum}{count}[/tex]
[tex]\frac{sum}{2}[/tex] = 13 ( multiply both sides by 2 )
sum of 2 eldest = 26
Then for the 4 children
average = [tex]\frac{26+2+4}{4}[/tex] = [tex]\frac{32}{4}[/tex] = 8