The following graph shows sales data of two products X and Y from 2015 to 2020 in Kgs. Study the graph of sales data carefully and answer the questions given below: Which of the following has the highest sales difference over the previous year?
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Subtract each year's value from the previous year for all four listed options and compare.
Step 1: Instead of computing all four values first, eliminate options by pairwise comparison. Product Y in 2016 gives $65770-55790=9980$ and Product X in 2016 gives $32230-23230=9000$; since $9980 > 9000$, drop Product X in 2016. Step 2: Product X in 2018 gives $40020-33450=6570$, which is less than $9980$, so drop this option too. Step 3: Product Y in 2018 gives $75070-67060=8010$, still less than $9980$, so it is dropped as well. Step 4: The only option surviving every comparison is Product Y in 2016. \[\boxed{\text{Product Y in 2016}}\]
