Question

Grace starts with 100 milligrams of a radioactive substance. The amount of the

substance decreases by each week for a number of weeks, w. She writes the
expression 100(-)w to find the amount of radioactive substance remaining after w
weeks.
Ryan starts with 1 milligram of a radioactive substance. The amount of the substance
decreases by 40% each week for a number of weeks, w. He writes the expression (1 -
0.4)" to find the amount of radioactive substance remaining after w weeks.
Use the drop-down menus to explain what each part of Grace's and Ryan's
expressions mean.

Answer 1

100 is grace's initial amount. w is how much of the substance is being decrased each week. in ryan's equation, 1 is 100% of the substance, so the initial amount, and 0.4 is the amount that is being decreased.

Explanation:

Answer 2

100= Initial Amount

1/4= decay factor for each week

w= number of weeks

1/4w= decay factor after w weeks

1 - 0.4= decay factor for each week

w= number of weeks

0.4= percent decrease

Explanation: