Hello,
let's assume j the john's age, m the mary's age.
<span>"John is twice as old as mary"==>j=2*m
</span>
<span>"the sum of their ages is 21" ==>j+m=21
==>2*m+m=21
==>3m=21
==>m=7
and j=21-7=14
</span>
Answer:157/1000
Step-by-step explanation:
Answer: x =10
Step-by-step explanation:
I'm sorry if its not right
