Troy needs to buy a rod, reel, lures, line, and a license to go fishing. The sporting goods store has a rod for $67, a reel for $42, a lure for $8 and a line for $11. The license will cost $38. Round each cost to the nearest 10 and then choose the best estimate of the total cost of paying for these five items.

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.