Can someone me with this problem? show the work one how to do it. 20 points

the main street market sells oranges at $3.00 for 5 pounds and apples at $3.99 for 3 pounds. the off-market sells oranges at $2.59 for 4 pounds and apples at $1.98 for 2 pounds.

(a). find the unit price for each item at each store.

(b) which store has the better buy for oranges? for apples?

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?