Unless otherwise prohibited, drivers must use the three-point turn to
pass another vehicle on a narrow road.
change lanes.
make a left turn.
turn around on a narrow street.

You are thinking of making your mansion more energy efficient by replacing some of the light bulbs with compact fluorescent bulbs, and insulating part or all of your exterior walls. each compact fluorescent light bulb costs $4 and saves you an average of $2 per year in energy costs, and each square foot of wall insulation costs $1 and saves you an average of $0.20 per year in energy costs.† your mansion has 150 light fittings and 3000 sq ft of uninsulated exterior wall. to impress your friends, you would like to spend as much as possible, but save no more than $750 per year in energy costs (you are proud of your large utility bills). how many compact fluorescent light bulbs and how many square feet of insulation should you purchase? how much will you save in energy costs per year? (if an answer does not exist, enter dne.)

Bonds often pay a coupon twice a year. for the valuation of bonds that make semiannual payments, the number of periods doubles, whereas the amount of cash flow decreases by half. using the values of cash flows and number of periods, the valuation model is adjusted accordingly. assume that a $1,000,000 par value, semiannual coupon us treasury note with three years to maturity has a coupon rate of 3%. the yield to maturity (ytm) of the bond is 7.70%. using this information and ignoring the other costs involved, calculate the value of the treasury note:

Alarge tank is filled to capacity with 500 gallons of pure water. brine containing 2 pounds of salt per gallon is pumped into the tank at a rate of 5 gal/min. the well-mixed solution is pumped out at the same rate. find the number a(t) of pounds of salt in the tank at time t.