In 2008, an estimated 7.8 million Mexican-born immigrants were employed in the United States.

a. If 60 percent of the Mexican-born immigrants remitted money to family members in Mexico in 2008, and if they each sent $100 per month, how much money did they remit in total for the year?

b. If, instead, 100 percent of the Mexican-born immigrants remitted money to family members in Mexico in 2008, and if they each sent $250 per month, how much money did they remit in total for the year?

c. The actual amount remitted to Mexico in 2008 by Mexican-born immigrants living in the United States was about $22 billion. If we assume that 75 percent of the Mexican-born immigrants remitted money to Mexico that year and if we further assume that each of those immigrants remitted an equal amount each month, how much per month did each of those immigrants have to remit to total $22 billion for the year?