The average of sales of a furniture shop in the years 2015, 2016, 2017, 2018 is ₹16300, and that for years 2016, 2017, 2018, 2019 is ₹18450. If the sales in 2019 are ₹9200, then what are the sales in 2015?

₹600

Sum of sales in 2015, 2016, 2017, 2018 = 4 ×16300 = 65200

Sum of sales in 2016, 2017, 2018, 2019  = 4 × 18450 = 73800 

Sale  in 2019 = 9200

Sum of sales in 2016, 2017, 2018 = 73800 - 9200 = 64600

Sale in 2015 = 65200 - 64600 = 600