1.

Suppose c(x) = x³- 20x²+ 20,000x is the cost of manufacturing x items. Find a production level that will minimize the average cost of making x items.

a)

10 items

b)

11 items

c)

12 items

d)

9 items

2. Use the formula R = log, I/I0 where the magnitude of an earthquake on the Richter scale is based on I, the measurement of a seismic wave, and I₀, the measurement of a seismic wave of a level zero earthquake with the same epicenter. If an earthquake measured 4.2 on the Richter scale, what was the intensity of the earthquake? (Round to whole number.)

a)

15,849

b)

1585

c)

67

d)

12,589

3.

How long will it take a sample of radioactive substance to decay to half of its original amount, if it decays according to the function A(t) = 200e^-0.171t, where t is the time in years? Round your answer to the nearest hundredth year.

a)	4.05 years

b)	30.98 years

c)	35.04 years

d)	34.20 years

4. Find the inverse of the function. f(x) = 8^x+ 3

a)	f-1(x) = log8(x - 3)

b)	f-1(x) = log8(x + 8)

c)	f-1(x) = log8(x + 3)

d)	f-1(x) = log8(x - 8)

5.

A retail store buys200VCRs from a distributor at a cost of $215each plus an overhead charge of $40per order. The retail markup is45% on the total price paid. Find the profit on the sale of one VCR.

a)

$96.66

b)

$9684.00

c)

$96.84

d)

$96.75

6. An organization determines that the cost per person of chartering a bus is given by the formula C(x)=300+7x/x where x is the number of people in the group and C(x) is in dollars. Find a formula for the inverse of this function.

a)	C-1(x)= 300+x/7

b)	C-1(x)=300/x+7

c)	C-1(x)= 300/x-7

d)	C-1(x)= 7/x-300