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%


Sagot :

[tex]\sf~I=prt[/tex]

Plug in what we know:

[tex]\sf~622.5=(12450)r(1)[/tex]

Multiply:

[tex]\sf~622.5=12450r[/tex]

Divide 12450 to both sides:

[tex]\sf~r=0.05[/tex]

Multiply by 100:

[tex]\sf0.05\times100=5\%[/tex]

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 = [tex] \frac{Value_n_e_w - Value_o_l_d}{Value_o_l_d} *100 [/tex]


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

% of interest earned = [tex] \frac{13072.5 - 12450}{12450} * 100 [/tex] = 5%


Hope this helps :)