Answer:
An equation:

Original number of strawberries are 40
Explanation:
Let X be the original number of strawberries.
As per the statement:
You eat 8 strawberries and your friend eats 12 strawberries from a bowl.
Total strawberries eat from a bowl = 8 + 12 = 20
Since, X is the original number of strawberries.
Remaining left strawberries in the bowl = X- 20
It is also given that: there are 20 strawberries left
⇒

We get an equation:

Add 20 to both sides we get;

Simplify:

Therefore, the original number of strawberries are 40