Write a system of linear equations in three or four variables to solve Exercises 47–50. Then use matrices to solve the system.

Imagine the entire global population as a village of precisely 200 people. The bar graph shows some numeric observations based on this scenario.

Combined, there are 183 Asians, Africans, Europeans, and Americans in the village. The number of Asians exceeds the number of Africans and Europeans by 70. The difference between the number of Europeans and Americans is 15. If the number of Africans is doubled, their population exceeds the number of Europeans and Americans by 23. Determine the number of Asians, Africans, Europeans, and Americans in the global village.

Number of People 150 125 100 75 50 25 ****** Earth's Population as a Village of 200 People Under age 15 60 Over age 65 ***** 14 **** ********** W *** Asian African x European Unable to read or write American (U.S.) 32 Z Eat at McDonald's each day