Let the random variable x denote the number of network blackouts in a day. the
probability mass function of x is:
x 0 1 2
p(x ) 0.7, 0.2, 0.1
a small internet trading company estimates that each networkblackout results in a $500 loss. compute expectation and variance of this company 's daily loss due to blackouts

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?