In a science test devi scores 15 marks more than lixin . if devi obtains twice as many marks as lexin . find the number of marks lixin obtains.

What is the value of the expression below? 148+(-6)| + |– 35= 7|

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square

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?