Exercise 4The farmer above can purchase two types of fertilizer. A 50lb bag of crescent fertilizer has 5units of nitrogen 15 units of phosphorous and 5 units of potash and cost $12. A 50lb bag ofIslandfertilizer has 10 units of nitrogen 10 units of phosphorous and 30 units of potash and costs$16. For a given crop the farmer must make sure that it does not receive more than 100 units ofnitrogen and does not receive less than 120 units each of phosphorous and potash. How manybags of each type of fertilizer should the farmer purchase to minimize his cost ?