The figure shows a line graph and two shaded triangles that are similar: Which statement about the slope of the line is true?

A. It is fraction 1 over 2 throughout the line.
B. It is 2 throughout the line.
C. The slope from point O to point A is fraction 1 over 2 time the slope of the line from point A to point B.
D. The slope from point O to point A is two times the slope of the line from point A to point 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.