Answer:
15 rounds Shilpa played.
Explanation:
They tell us she earned 100 points in the first round, that's going to be a fixed value in the equation. Then, we know the won 20 points in every next round (20x). So, we will have the following: 100 + 20x = 400
Clear x:
20x = 400 - 100
20x = 300
x = 300/20
x = 15