Deepti went to school for 216 days in a full year. If her attendance is 90%, find the number of days on which the school was opened.

Explanation

To solve the problem step by step, we can follow these instructions:

### Step 1: Understand the problem
Deepti attended school for 216 days, and her attendance percentage is 90%. We need to find the total number of days the school was opened in the year.

### Step 2: Set up the equation
Let the total number of days the school was opened be represented by \( X \). According to the problem, Deepti attended 90% of the total days. Therefore, we can write the equation:
\[
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