Mr ferry owns a cow, a horse, and a goat. cow eats 2 1/2 kilograms of grass per day
horse eats 1 1/2 kilo of grass per day
goat eats 3/4 kilo of grass per day

how many kilo of grass should mr ferry buy to feed his 3 animals for 30 days.

if grass costs 125.50 per kilogram. how much will the 30 day supply of grass cost?​

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?