7y+11+7y+11+7y+11=180(A.S.P)
21y+33=180
21y=180-33
21y=147
y=147/21
y=7
y=7
Answer:
The treatment decays by half each week.
Step-by-step explanation:
The decay function is given by:

Here,
<em>y</em> = final value
<em>a</em> = initial value
<em>r</em> = decay rate
<em>t </em>= time
The decay function for one medications to treat dogs for fleas is:

Here the decay rate is:

The treatment decays by half each week.