An animal shelter spends $3.50 per day to care for each bird and $4.00 per day to
care for each cat. Madelyn noticed that the shelter spent $82.00 caring for birds and
cats on Thursday. Madelyn found a record showing that there were a total of 22 birds
and cats on Thursday. How many birds were at the shelter on Thursday?

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.