After 6 hours the amount of caffeine 40 mg. After another 6 hours the amount of caffeine is 20 mg. It takes 12 hours for the total amount of caffeine to drop down to 20 mg. the answer is 11 am -B. Hope this helps!
Is there an attachment to this? It cant be answered without a picture or a description.
Answer:

Step-by-step explanation:
Given




Required
Determine the new coordinate of J
From rules of rotation,
When a point (x,y) is rotated 270 degrees CCW;
The new point becomes (y,-x)
Considering point J

This means

Where
and 
Using the above rotation rule of

The coordinates of J' becomes

Answer:
6
Step-by-step explanation: 31.50 devided by 5.25 = 6