Steve invested $4,000$4,000 in a savings account. The interest rate is 3.5%3.5% per year. Find the interest earned if the amount was kept in the bank for 33 years.
Mary invested $3,000$3,000 in a savings account. The interest rate is 9.5%9.5% per year and is not compounded. Find the interest earned if the amount was kept in the bank for 1010 months.
We are given a rate per annum, so we need to solve for the rate per month
Rate per month
==
Rate (r)(r) per annum ÷12÷12
==
0.0950.095÷12÷12
==
0.007920.00792
Interest rate per month
Solve for the Interest (I),(I), using the formula
II
==
PPrrtt
Simple Interest Formula
==
$3,000$3,000××0.007920.00792××1010
Plug in the known values
==
$237.50$237.50
$237.50$237.50 interest earned
Question 3 of 5
3. Question
If you put money into a savings account that earns $147.00$147.00 over seven years at a rate of 3%3%, how much money did you put into the account?
Principal=$=$(700)
Correct
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Incorrect
Simple Interest Formula
I=PrtI=Prt
Labelling the given values
Interest=I=$147=I=$147
Principal Value=P=?=P=?
Rate=r=3%=r=3% per annum
Time Elapsed=t=7=t=7 years
First, express the rate as a decimal
3%=0.033%=0.03
Solve for the Principal (P),(P), using the formula
II
==
PrtPrt
Simple Interest Formula
$147$147
==
P×0.03×7P×0.03×7
Plug in the known values
$147$147
==
P×0.21P×0.21
Simplify
$700$700
==
PP
Divide both sides by 0.210.21.
PP
==
$700$700
Reverse the sides so that the unknown variable PP is on the left-hand side.
The Principal is $700$700.
Question 4 of 5
4. Question
How much interest is earned on a principal of $200 invested at an interest rate of 6% for eight years?
Interest Earned=$=$(96)
Correct
Keep Going!
Incorrect
Simple Interest Formula
I=PrtI=Prt
Labelling the given values
Interest=I=?=I=?
Principal Value=P=$200=P=$200
Rate=r=6%=r=6% per annum
Time Elapsed=t=8=t=8 years
First, express the rate as a decimal
6%=0.066%=0.06
Solve for the Interest (I),(I), using the formula
II
==
PrtPrt
Simple Interest Formula
==
$200×0.06×8$200×0.06×8
Plug in the known values
==
$96$96
$96$96 interest earned
Question 5 of 5
5. Question
If an investment over eight years that gives $160.00$160.00 in interest results in a final balance of $610.00$610.00, what was the original investment?
Principal=$=$(450)
Correct
Keep Going!
Incorrect
Simple Interest Formula
I=PrtI=Prt
Labelling the given values
Interest=I=$160=I=$160
Principal Value=P=?=P=?
Rate=r=?=r=? per annum
Time Elapsed=t=8=t=8 years
Solve for the Principal (P),(P), by subtracting the final total $610$610 from the interest earned $160$160.