Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks. Two students in the same Spanish class, Francesca and Emmy, plan to get together after school to make vocabulary flashcards. Francesca started on the project yesterday and has already made 6 flashcards. Emmy hasn't started yet. Since Francesca makes 5 flashcards per minute and Emmy makes 6 flashcards per minute, Emmy will soon have the same number of flashcards. How many flashcards will each student have at that point? How long will that take?

Francesca and Emmy will each have _ flashcards in _ minutes.

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?