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Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

Me because some of question i don’t understand

The customer price index(cpi), which measures the cost of a typical package of customer goods, was 208.8 in 2011 and 244.1 in 2016.let x=11 corresponding to the year 2011 an estimate to cpi into 2013 and 2014. assume that the data can be modeled by a straight line and the trend to continue idenfinitely. use data points to find such a line and then estimate the requested quantities