How do you solve this? i am having a real hard time on where i need to start, .

An airport in death valley is 60 feet below sea level, and an airplane is flying 2,000 feet above sea level. how many feet must the plane descend in order to land? a. 2060 b. 2000 feet c. 1940 feet d. 1880 feet e.1400 feet will mark as brainliest

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?

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.