Perform the addition of polynomials (middle school math pls help!)

42. if 20 men can eat 200 kg of wheat in 40 days, then 10 men can eat 300 kg of wheat in how many days? a) 120 days b) 60 days c) 80 days d) none of these

Find the percent error of the measurement 4 cm

Solve for x -3+3b> 9a: ) x> 4b-9/3b: ) x< 9-4b/3c: ) x< -4b+9/-3d: ) x> 4b+9/-3