Last year, Amy opened an investment account with $6400. At the end of the year, the amount in the account had increased by 21.5%. How much is this increase in dollars? How much money was in her account at the end of last year?

Can you me find the missing length. i attached an image.

Write the standard form of an equation with (see picture below)

There are a total sales of 2,000 dollars on monday on tuesday sales dropped 10% on wednesday sales dropped another 20% compared with tuesday from wednesday to thursday sales increases by an equal amount to 25% of monday total sales what is the net change in dollars on total sales from monday to tuesday