11-15. Red cedar costs $1.50 per board foot. You need 8 boards each 1 inch thick, 6 inches wide, and 8 feet
long to complete a planter box. Calculate the cost of the
lumber needed to complete the project. YOU MUST SHOW
YOUR MATH TO GET CREDIT

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.