13. a square piece of cardboard measuring 120 inches on a side is made into a rectangular box by cutting identical squares from the four corners and then folding up the flaps. Let x represent the length of the side of each discarded square. Write a formula for the volume of the box in terms of x, What value of x will result in the larger volume of the box? what is that volume?

16. At the beginning of the year 2000 the world population was approximately 6 billion. Suppose that the population is described by the exponential growth model Q(t)=qoe^et and the rate of the growth is 1.1% per year. Give the approximate world population by the beginning of the year 2100.

ANSWER ALL PLEASE

18. A 40-year old wants to retire at age 65. How much money should be invested at 5.5% interest compounded continuously to provide the sum of $500,000 upon retirement?

22. A movie theater changes $10.00 admission for an adult and $6.00 for a child. On a particular day 400 tickets were sold and the total received was $3000. How many tickets of each type were sold?

23. A part of $20,000 was invested at an interest rate of 6% and the remainder at 8%. If the total interest received at the end of 1 year is $1300 how much was invested at each rate?

24. A supermarket mixes coffee that sells for $3.60 per pound with coffee that sells for $7.20 per pound to obtain 200 pounds of coffee selling for $6.00 per pound. How much of each type of coffee should be used?