Lin is working on a science experiment. She wants to determine whether salt water boils faster than freshwater. She collects 10 samples of 100 milliliters of salt water and 10 samples of 100 milliliters of freshwater. She places each sample in a beaker on a hot plate. She then records the time it takes to boil for each group and find that the difference in mean times for the groups is 24 seconds.

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?