David told jen, "write three two-digit numbers. i'll add three more and give you the sum right away." jen wrote 53, 42, and 31.then david wrote 46, 57, and 68 and said the sum was 297. was he right? what pattern did he use?

The volume of a cube-shaped shipping container is 13,824 cubic inches. find the edge length of the shipping container.

Use the elimination method to solve the systems of equations. choose the correct ordered pair. 7x+4y=39

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?