We solve for the percentage that the sales in 2018 as a representative of the base is calculated by computing for the difference by the two amounts.
Difference = ($78,000 - $65,000) = $13,000
Then, we divide the difference by the base value,
= ($13,000) / ($65,000) = 0.2
Then, we multiply the calculated ratio by 100%.
Percentage = (0.2) x 100% = 20%
Then, we add 100% to the answer.
Hence, 2018 sales represent 120% of the base sales during the year 2016.
Similarly, we can just divide the given sales on 2018 by the base sale on 2016.
ANSWER : 120%