A bag of marbles had 20 red marbles and the rest were black. For a game, 4/5 of the 20 red marbles were chosen, and 24 of the black marbles were also chosen. How many black marbles were in the bag before the game?

Match each inequality to the number line that represents its solution

W-16=-12 solve each one step equation plz

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?