Which equation and solution can be used to solve this problem? Thirteen less than a. number is sixteen. 1. 13-n=16: Add 13 to both sides. The answer is 29.
2. n+13=16: Subtract 13 from both sides. The answer is 3
3. n+16=13: Subtract 13 from both sides. The answer is 3
4. n-13=16: Add 13 to both sides. The answer is 29

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.