Select the items for which the discount is greater than 15%.circle all that apply. plz show me work
a)$29.95 box set of cds on sale for $19.95
b)$64.49 pair of shoes on sale for $55
c)$85 radio on sale for $74.49
d)$145 suitcase on sale for $114.99

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?