Final AMC Review Time

How many ordered triples  $\left(a,\ b,\ c\right)$ of nonzero real numbers have the property that each number is the product of the other two?

• 1

• 2

• 3

• 4

• 5

Roy bought a new battery-gasoline hybrid car. On a trip the car ran exclusively on its battery for the first 40 miles, then ran exclusively on gasoline for the rest of the trip, using gasoline at a rate of 0.02 gallons per mile. On the whole trip he averaged 55 miles per gallon. How long was the trip in miles?

• 140

• 240

• 440

• 640

• 840

• 9

• 10

• 11

• 12

• 13

Suppose that $a$ and $b$ are nonzero real numbers, and that the equation $x^2\ +\ ax\ +\ b$ has solutions $a$ and $b$ . Then the pair $\left(a,\ b\right)$ is

• (-2, 1)

• (-1, 2)

• (1, -2)

• (2, -1)

• (4, 4)

• 50

• 52

• 54

• 56

• 58