Between -2&-1 is the answer
Answer: 
Step-by-step explanation:
Given
Cost per student in the year 1978 is $2200
The cost increases to $10,300 in 2008
Suppose 
is the linear equation defining the cost per student after x years
Substitute the value for 1978
After 30 years it becomes
Thus, the linear equation becomes
Answer:
141
Step-by-step explanation:
There would be 260 lifegurads
The easy way is to divide 18.2 by 0.07 to get your answer
If my answer is wrong pls let me know i try my best to edit and make it right
This is exponential decay which can be expressed as:
y=ab^t, y=final value, a=initial value, b=rate, t=time
In this case a=25000, r=(100-20)/100=0.8 so
y=25000(0.8^t), so in 4.5 years...
y=25000(0.8^4.5)
y≈$9158.93 (to nearest cent)
