The number of people using an older version of a spreadsheet program decreases at a rate that is proportional at any time to the number of people still using the version at that time.

There were 10,000 people using the older version of the spreadsheet program when the new version first came out. The number of people still using the older version decreases by 20%, percent every 6 months.

y = 2x

step-by-step explanation:

if you divide each number in the sequence, you'll see that they all have a multiple factor of 2. each number in the series, and any other numbers which may continue, will be multiplied by 2. therefore, y is the next number in the sequence, and x is the current one, so, our formula will be y = 2x.

$5.41

step-by-step explanation:

$20 - $14.51 = $5.49.

144.50

step-by-step explanation:

21.5 x 13.4=288.10 divide by 2