Personally (interaction or help) online by Arif Sir for IIT-JEE / NEET / BOARDS @ Rs. 5000 annually. (English & Hindi medium both) Contact : +91-9415441100 This video is made on a problem asked in a competitive exam based on Archemede's principle. Download theory notes:http://www.arifacademy.com/class%2011... For more information log on to: www.arifacademy.com If you are preparing for IIT-JEE / NEET / AIIMS or Class XI and XII You can send your problems or doubts on my Whatsapp number 9369110100. I will make video on your problems and send you.