Equations are used in solving problems. Explain a real-life instance and express the situation using an equation. Explain how you went about finding a solution to the problem. (For e. g., we want to go to zoo. 7 adult tickets and 7 kids tickets equal 50 dollars. Adult tickets are twice as expensive as the kid’s ticket. How much do the tickets cost?)

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?