In this question, we want to know how much will be in the account after 3 years. Thus, we need to find an equation and since it's an exponential growth, we use the formula
A(t)=a(1+r)t. We know that Katinka's initial deposit was $2000, so a=2000. Further, the rate is r=0.04 since 4%=0.04.A(t)=2000(1+0.04)t
We can substitute 3 for t, since it's 3 years, in our equation and solve for A(t).
Thus, we see that after 18 years in the account Katinka will have $4060.
c
In this case, we want to find out when Katinka's total amount will be $2500 so she can afford the trip. We can substitute $2500 for A(t) and then solve for t.
Thus, Kantinka needs to save money for 5.69 years.
d
In this case, we want to find out when Katinka's total amount will be $3000 so she can afford the trip to LA. We can substitute $3000 in for A(t) and then solve for t.
