Oscar is comparing two cell phone companies and needs to make a decision about which company is best for him. Company A charges a startup fee of $50 and $40 each month after that. Company B charges a startup fee of $110 and $30 per month. The equations below model the two companies’ total charges, T, after m months. Company A: T = 40m + 50 Company B: T = 30m + 110 After how many months would Oscar pay the same amount for Company A and Company B?

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?