We have been given that Clare made $160 babysitting last summer. She put the money in a savings account that pays 3% interest per year. If Clare doesn't touch the money in her account, she can find the amount she'll have the next year by multiplying her current amount 1.03.
We are asked to write an expression for the amount of money Clare would have after 30 years if she never withdraws money from her account.
We will use exponential growth function to solve our given problem.
An exponential growth function is in form
, where
y = Final value,
a = Initial value,
r = Growth rate in decimal form,
x = Time.

We can see that initial value is $160. Upon substituting our given values in above formula, we will get:


To find amount of money in Clare's account after 30 years, we need to substitute
in our equation.

Therefore, the expression
represents the amount of money that Clare would have after 30 years.
9514 1404 393
Answer:
Step-by-step explanation:
The decay factor is 1 -25% = 0.75 per hour, so the exponential equation can be written ...
r(t) = 1450·0.75^t . . . . . milligrams remaining after t hours
__
a) After 4 hours, the amount remaining is ...
r(4) = 1450·0.75^4 ≈ 458.79 . . . mg
About 459 mg will remain after 4 hours.
__
b) To find the time it takes before the amount remaining is less than 5 mg, we need to solve ...
r(t) < 5
1450·0.75^t < 5 . . . . use the function definition
0.75^t < 5/1450 . . . . divide by 1450
t·log(0.75) < log(1/290) . . . . . take logarithms (reduce fraction)
t > log(1/290)/log(0.75) . . . . . divide by the (negative) coefficient of t
t > 19.708
It will take about 20 hours for the amount of the drug remaining to be less than 5 mg.
Answer:
From the graph, when x=-6, y=1
so, your answer is A) f(x)=∛(x-6)+1
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