Question

Alice earned $622.50 in interest on her savings in the bank. Before interest, the account had $12,450. What is the approximate percent she earned in interest?
3%
5%
7%
10%

Answer 1

Answer:

5%

Explanation:

% she earned in interest can be calculated by calculating the % of increase in the balance

We have:

Original balance = $12,450

Amount of interest = $622.5

This means that:

new balance = 12,450 + 622.5 = $13,072.5

Now, we can get the percentage of increase:

% of increase = $\frac{Value_n_e_w - Value_o_l_d}{Value_o_l_d} *100$

Substitute with the values we have to get the percentage of interest earned as follows:

% of interest earned = $\frac{13072.5 - 12450}{12450} * 100$ = 5%

Hope this helps :)

Answer 2

$\sf~I=prt$

Plug in what we know:

$\sf~622.5=(12450)r(1)$

Multiply:

$\sf~622.5=12450r$

Divide 12450 to both sides:

$\sf~r=0.05$

Multiply by 100:

$\sf0.05\times100=5\%$