The multi-layered pie-chart below shows the sales of LED television sets for a big retail electronics outlet during 2016 and 2017. The outer layer shows the monthly sales during this period, with each label showing the month followed by sales figure of that month. For some months, the sales figures are not given in the chart. The middle-layer shows quarter wise aggregate sales figures (in some cases, aggregate quarter-wise sales numbers are not given next to the quarter). The innermost layer shows annual sales. It is known that the sales figures during the three months of the second quarter (April, May, June) of 2016 form an arithmetic progression, as do the three-monthly sales figures in the fourth quarter (October, November, December) of that year. Data shown in the chart ("?" = not given): 2016: January 80, February 60, March 100 (Q1 ?); April 40, May ?, June ? (Q2 150); July 75, August 120, September 55 (Q3 ?); October 100, November ?, December ? (Q4 360). 2017: January 120, February 60, March 160 (Q1 ?); April 60, May 75, June 65 (Q2 ?); July 60, August ?, September 70 (Q3 220); October 150, November 170, December ? (Q4 500). [Figure: see page 13 of source PDF]