If the original price of sugar is Rs "p" per kg, then the given information can be written in equation form as 80/(p(1-.20)) - 80/p = 4 Multiplying by p/4, we get 80/(4(.80)) - 80/4 = p 25 - 20 = p 5 = p

**The original price of sugar was Rs 5 per kg**.__Check__At the original price, the purchaser could get 80/5 = 16 kg. At the reduced price of Rs 4 per kg, the purchaser could get 80/4 = 20 kg The purchaser is able to buy 20 - 16 = 4 kg more at the reduced price.