A wholesale wheat seller sells 0.8 grams of wheat instead of 1 gram at a rate of Rs. 15 per kg. A retail shopkeeper purchases 100 kg wheat from the wholesale wheat seller and sells it to a small shop keeper so that he earns a profit of Rs. 100. By the time it reaches the small shopkeeper 20% of the wheat became spoilt. In order to escape from loss, how much should 1 kg of wheat be sold at?