Answer:D
Step-by-step explanation:
P=1/5. factor out the p to get 4p-15pn=4/5p-3n and just solve to get p=1/5
Answer: 
Step-by-step explanation:
We know that the general form of the exponential decay formula is
, where y is final amount remaining after t time, A is the original amount and r is the rate of decay
Now, the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident. 
Hence, the ratio of remaining since the nuclear accident is 
A two-dimensional net is useful because it flattens the 3-d figure so that you can see all the faces of the figure. You can calculate the area of each face to find the surface area.
6 times 20 equals 120 and equals 26 when added together