Can someone help me understand proofs?

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

Atriangle in the coordinates of (2,3), (-4,5) and (-2,4) it is translated 3 units down. what are it’s new coordinates

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?