Which of the following is true? achecks and debit cards both withdraw money directly from a bank account. bdebit cards often have a higher interest rate than credit cards. cchecks are the most widely accepted form of payment ddebit cards offer the highest level of fraud protection.

Answer the following questions using the data given below. annual percent return on mutual funds (n = 17) last year (x) this year (y) 11.9 15.4 19.5 26.7 11.2 18.2 14.1 16.7 14.2 13.2 5.2 16.4 20.7 21.1 11.3 12.0 –1.1 12.1 3.9 7.4 12.9 11.5 12.4 23.0 12.5 12.7 2.7 15.1 8.8 18.7 7.2 9.9 5.9 18.9

The market for corn in country a is highly competitive. at the current market price of $5/bushel there is a shortage of 100,000 bushels of corn in this country. media reports claim that the price of corn will rise drastically in the near future. according to these reports, the neighboring country b had witnessed a similar situation recently. at the same price, the shortage in country b was also 100,000 bushels and eventually the equilibrium price in b went up to $10/bushel. both countries are known to have equal number of corn producers and the market supply of corn is identical at all prices. this, combined with the fact that consumers in the two countries also have similar tastes and preferences, led the media to conclude that the price of corn in country a would soon be as high as $10/bushel. the new equilibrium price turns out to be below $10/bushel, what inferences can be drawn?

Problem page a medical equipment industry manufactures x-ray machines. the unit cost c (the cost in dollars to make each x-ray machine) depends on the number of machines made. if x machines are made, then the unit cost is given by the function =cx+−0.3x2126x31,935 . how many machines must be made to minimize the unit cost?