PLEASE HELP! I am having trouble with both questions

99 % of the trees in our neighborhood are eucalyptus trees. The town planning commission wants to get rid of some of these trees

Brut [27]

Answer:

50%

Step-by-step explanation:

Let the total number of trees be T and suppose that this is made up of eucalyptus trees E and other kinds of trees, O.

Then E+O=T, and since 99% of the trees are eucalyptus trees, EE+O=0.99.

Therefore

0.99E+0.99O=E

0.01E=0.99O

E=99O.

Suppose we reduce the number of eucalyptus trees by some amount x and that the remaining number of eucalyptus trees are now 98% of the total trees.

Then we would have E−x(E−x)+O=0.98.

Therefore,

0.02(E−x)=0.98O

0.02E−0.02x=0.98O

0.02x=0.02E−0.98O

x=E−50(0.98)O

x=E−49O

x=E−49(E99)

x=5099E≈0.505050...×E.

So we end up removing a little over half of the eucalyptus trees. EDIT: Forgot to mention - removing 50.505050...% of the eucalyptus trees means that we are removing 0.50505050....×0.99T which is 0.5T or half the trees in the neighborhood.

3 0

3 years ago

Suppose Miss Roxanne Davenport is 25 years old right now and puts away $1,800 per quarter in an account that returns 6% interest

Lena [83]

We have been given that miss Roxanne is 25 years old and she puts 1800 dollars per quarter that returns 6% interest.

(a) We need to figure out how much will be in the account when she turns 65 years old. When she turns 65 years old, the number of years during which she made deposits would be 40. Since she made quarterly deposits. She made a total of 160 deposits. We can now figure out the final amount in the account using future value of annuity formula.

$A=P\frac{(1+r)^{n}-1}{r}$