Integer means a whole number , a number that is not fraction
Katie did not specifically said what numbers , the numbers can be fraction and it would not be called integer so that is Katie's error
Answer:
a)
, b)
, c)
, d) 
Step-by-step explanation:
a) Let assume an initial mass m decaying at a constant rate k throughout time, the differential equation is:

b) The general solution is found after separating variables and integrating each sides:

Where
is the time constant and 
c) The time constant is:


The particular solution of the differential equation is:

d) The amount of radium after 300 years is:

Answer:

Step-by-step explanation:
It starts with a base cost of $5.25 and increases by $2.50 for every ticket sold. Add 2.50(number of tickets) to the admission cost to get the total cost.
the sum of 7/3+ (-3/8) is 47/24. Hope it helps