The Environmental Protection Agency says on its website that "You can save up to 8 gallons of water by turning off the faucet when you brush your teeth in the morning and before bedtime." a. Estimate how much water a family of four would use each week, assuming they left the water running while brushing.
b. Estimate how much water would be saved in one day if the entire United States turned off the faucet
while brushing.
c. Put your answer to the previous question in context (compare it to the volume of water in a lake or swimming pool, for example).

With number 11 ( show how you got the answer)

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?

Care repairs are less than or equal to $500