What is the acceleration of the particle at time t=3?

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Noor brought 21 sheets of stickers. she gave 1/3 of a sheet to each of the 45 students at recess. she wants to give teachers 1 1/2 sheets each.

Aball is dropped from a height of 10m above the ground. it bounce to 90% of its previous height on each bounce. what is the approximate height that the ball bounce to the fourth bounce?