Landon and his children went into a bakery and will buy donuts and brownies. Each donut costs $1 and each brownie costs $3. Landon has a total of $15 to spend on donuts and brownies. Write an inequality that would represent the possible values for the number of donuts purchased, ddd, and the number of brownies purchased, b. B.B.

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.