Half life can be used to solve for the amount (A) of a substance left after t time by using the following equation: A=Av(0)⋅(12)^(t/h)

If the half life of a substance is 2 days, how long will it take for 100 mg of this substance to decay to 12.5 mg?

Select one:
A. 10 days
B. 4 days
C. 8 days
D. 6 days

6 days

Step-by-step explanation:

what are the options? ?

step-by-step explanation:

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."