Why does long division even exist

Solve - pv + 40 < 65 for v solve 7w - 3r = 15 for r

5500 dollars is placed in an account with an annual interest rate of 6.5%. to the nearest tenth of a year, how long will it take for the account value to reach 19700 dollars?

You are remodeling your kitchen. you’ve contacted two tiling companies who gladly told you how long it took their workers to tile of a similar size jim completed half the floor in 8 hours. pete completed half of the other floor in 7 hours. if pete can lay 20 more tiles per hour than jim, at what rate can jim lay tiles