Solve the following word problem by using a system of equations.
jake and his friends went to the carnival. the total number of ice cream sandwiches and sodas purchased among all of them was 18. one ice cream sandwich costs $2.25 and a soda costs 75¢. in total, $30.00 was spent on ice cream and soda.
which statement is true?
a. jake went to the carnival with 8 of his friends.
b. jake and his friends bought a total of 11 ice cream sandwiches.
c. jake and his friends bought a total of 11 sodas.
d. jake and his friends spent more on sodas than ice cream sandwiches.

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?