**Solution:**

To find out how many months Meena will take to save ₹39000, we need to calculate the amount Meena saves each month and then divide the total savings required by the monthly savings amount.

Let's break down the solution into the following steps:

**Step 1: Calculate Meena's monthly savings amount:**

Given that Meena spends 0.75 of her salary every month and she earns ₹12000 per month, we can calculate her monthly savings amount as follows:

Savings = Salary - Expenses

Expenses = 0.75 * Salary

Savings = Salary - 0.75 * Salary

Savings = 0.25 * Salary

Savings = 0.25 * ₹12000

Savings = ₹3000

So, Meena saves ₹3000 per month.

**Step 2: Calculate the number of months required to save ₹39000:**

To calculate the number of months required, we divide the total savings required by the monthly savings amount:

Number of months = Total savings required / Monthly savings amount

Number of months = ₹39000 / ₹3000

Number of months = 13

Therefore, Meena will take 13 months to save ₹39000.

**Conclusion:**

Meena will save ₹3000 per month and she needs to save ₹39000. Therefore, it will take her 13 months to save the required amount.

In 3 1/2 mouths