Final answer:
To spray one acre using a combination of Doubt 8E and Lancer 1.5E, 2.125 lbs. of material is needed.
Step-by-step explanation:
To calculate how much material is needed to spray one acre using a combination of Doubt 8E and Lancer 1.5E, we need to find the total amount of active ingredient required.
For Doubt, the recommended rate is 2 lbs. of active ingredient per acre. For Lancer, the recommended rate is 0.125 lb. of active ingredient per acre.
To find the total amount of active ingredient needed, we add the recommended rates for Doubt and Lancer:
Total active ingredient = 2 lbs. + 0.125 lb. = 2.125 lbs.
Therefore, to spray one acre, we need 2.125 lbs. of material. Option d, which states Doubt 1 qt. and Lancer 2/3 pt., is the correct answer.