Acarpenter uses the equation y = 3.75x to determine how many hours (y) it will take him to build a desk (x). the carpenter built 5 desks. how long did it take him? a) 1 hour 33 minutes b) 1 hour 20 minutes c) 15 hours 10 minutes d) 18 hours 45 minutes

Olivia uses the work below to determine 55% of 720 which explains the error in olivia’s solution

The anwser cause i do not understand just plez

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?