The income tax policy for residents of a tiny island nation that uses U. S. Dollars as its currency is as follows: The first $20,000 of a citizen’s income is taxed at a rate of 10%. The next $30,000 of the citizen’s income is taxed at a rate of 18%. Any amount over $50,000 is taxed at a rate of 27%.

How much income tax would an individual with an income of x dollars be charged, where x is at least $50,000?

0.10(20,000) + 0.18(30,000) + 0.27x

0.10(x − 20,000) + 0.18(x − 30,000) + 0.27x

0.10(20,000) + 0.18(30,000) + 0.27(x − 50,000)

0.10(20,000) + 0.18(30,000) + 0.27(50,000 − x)

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.