The high school asked Amanda to paint a few murals around the school. Her mural in the cafeteria will show a ray of sunlight breaking through storm clouds. To create the perfect gray paint for storm clouds, Amanda models the proportional relationship between the number of cans of black paint, x, and the number of cans of white paint, y, with the equation y = 2x. If Amanda used 5 cans of white paint, how many cans of black paint did she use?

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?