A sample of the students at a middle school is selected by writing the name of every student in the school on a slip of paper and putting all the
names into a bin. The bin is then rotated to mix the slips of paper and 25
names are drawn without looking. If the bin is rotated after every draw,
which kind of sampling method is this?
OA) Non-random sampling
OB) Simple random sampling
OC) Stratified rondom sampling
OD Systematic random sampling

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?