An electric company calculates a person's monthly bill from the number of kilowatt-hours (kWh), x, used.
The function
b(c)
{
0.102,
X is greater than or equal to 200
0.15(x – 200) + 20, 2 > 200
determines the
bill.
How much is the bill for a person who uses 400 kWh in a month?

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?