Kindly help me to solve a b and c

Old = 5000 - 25 Pa + 30 Pb + 0.51 where, Pa = Price per unit of AmanJaya San Bhd soft drinks, Pb = Price per unit of the competitor's soft drinks, and I = Income of the consumer AmanJaya also has an inclination to set up soft drink outlets in petrol stations. Later the firm sets up soft drink outlets in a petrol station. The petrol station was located at a place where there were no other soft drink outlets within a radius of 5 km. In mid-2018, the firm offered a discount of 10% and sales jumped from 700 bottles per month to 1500 bottles per month. The discount was withdrawn subsequently. Happy by the response, six months later, the owner decided to permanently reduce the price of soft drinks by 10%. Meanwhile, two new soft drink outlets were set up in the area. This time to the owner's dismay, the sales went up marginally from 700 bottles per month to 800 bottles per month, and since a reduction in the price had already been announced, the owner could not revert to the old price. Questions: (a) Discuss whether the pricing strategy adopted by the company in the petrol station is right or not. (5 marks) (b) Calculate price elasticity of demand for soft drinks in petrol station outlets in mid-2018. (2 marks) (c) What factors have changed since then and what is the effect of these changed factors on the price elasticity, and the resultant new price elasticity