Answer:
11 = x - 1
Explanation:
We know that Anna is 1 year younger than Bo
We also know that Anna is 11 years old
We can use this info to set up an equation...
( Anna's age ) ( Bo's age ) ( difference between ages )
⇩ ⇩ ⇩
11 = X - 1
⇧
( we used subtraction sign to show that Anna's age is less )
We can test this out too!! by using simple maths we can hypothesize that Bo must be 12 years old since his sister is 1 year younger and currently 11
now we solve the equation we made...
11 = x - 1
Add one to both sides
+1 = +1
and our result is
12 = x
Meaning Bo is 12 years old.
I hope this helps you understand!! :)