(2) Original price of a mobilephone = Rs. 100 (let) Number of mobile phonessold = 100 Revenue received = 100 × 100= Rs. 10000 Case II, New price of a mobile phone= Rs. 80 New number of mobilephones sold = 180 ∴ Revenue received= Rs. (80 × 180) = Rs. 14400 Increase = 14400 – 10000 = Rs. 4400 ∴ Percentage increase =