7:9 because there are 35 children and 10 adults. Add 35 and 10 you get 35:45 then you simplify the ratio to get 7:9.
You can literally determine the sisters height by adding 4 + 3 because it says she’s 3 years older I’m not saying that she equation because the equation needs to include x so 4 + 3 = x
Answer:
Step-by-step explanation:

Add 5 to both sides

x = 6

Add 3 to both sides
x = -15 +3
x = -12
There's an app called photomath that would be useful for these kinds of problems!