Mark wants to be a millionaire by the time he retires at age 65. he assumes there is a 6% annual interest rate. if he starts saving at age 20, he will need to invest $4,700 each year. if he starts saving at age 30, he will need to invest $9,000 each year. how much more money will mark have to save if he starts saving at age 30 instead of age 20? a) $150,500 b) $103,500 c) $43,000 d) $4,482

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?