Question

example
pablo deposits $750 into a bank account. the account earns yearly simple
interest at a rate of $3\frac{1}{2}\\%$. how many years does it take pablo to earn a total
of $105 in simple interest?
use the simple interest formula and solve for t.
$p = \\$750, r = 3.5\\%, \text{and} i = \\$105$
$i = prt$
$105 = (750)(3.5\\%)(t)$
$105 = (750)(0.035)(t)$
$105 = 26.25t$
$4 = t$
it takes 4 years for pablo to earn $105 in interest.
1 suppose you deposit $1,200 into a bank account. the account earns yearly simple
interest at a rate of $1\frac{3}{4}\\%$. how many years does it take to earn a total of $126 in
simple interest? show your work.

solution
2 conan borrows $3,000 at a yearly simple interest rate of 1.0% for 2 years.
he owes ________ in interest. he needs to pay back ________ in all

vocabulary
simple interest
a percent of an
original amount that
is borrowed or
invested, paid an du
ered of a set period
of time

Explanation:

Step1: Define known values, use $I=Prt$

$P=\$1200$, $r=1\frac{3}{4}\%=0.0175$, $I=\$126$

Step2: Substitute values into formula

$126 = 1200 \times 0.0175 \times t$

Step3: Calculate product of $P$ and $r$

$1200 \times 0.0175 = 21$

Step4: Solve for $t$

$t = \frac{126}{21}$

Step1: Define known values, use $I=Prt$

$P=\$3000$, $r=1.08\%=0.0108$, $t=2$

Step2: Calculate interest owed

$I = 3000 \times 0.0108 \times 2$

Step3: Compute total payback amount

$\text{Total} = P + I$

Answer:

$t=6$ years

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