Rimi bought a mobile phone at a discount of 20%. Had the discount received was 25%, she would have saved Tk 2,000 more. How much did she pay (in Tk) for the mobile phone?

Solution:

Let the actual price of the phone be 100x

Cost price of Rimi = 100x × (100 - 20)%
⇒ 100x × 80%
⇒ 80x

If 25% discount is given then,
Cost price of Rimi = 100x × (100 - 25)%
⇒ 75x

According to the question,
80x - 75x = 2000
⇒ 5x = 2000
⇒ x = 400

So, actual cost price of Rimi = 80 × 400
⇒ 32000

∴ She paid 32000 (in Tk) for the mobile phone.