'' aluminum can pull tabs collected by students''

class number of pull tabs collected

boys 65
girls 72

the environment club collected pull tabs from aluminum drink cans to raise money. their goal was to collect 175 pull tabs. which equation can be used to find the number of pull tabs (p) needed to reach their goal.
(a) 175 - 65 = p
(b) 175 + 65 = p
(c) 175 - 137 = p
(d) 175 + 137 = p

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?