Given [tex]$I=\$ 290.50$[/tex], [tex]$P=\[tex]$ 1,000$[/tex][/tex], and [tex]$t=7$[/tex], solve for [tex]r[/tex].

A. [tex]r=1.45 \%[/tex]
B. [tex]r=4.15 \%[/tex]
C. [tex]r=28.85 \%[/tex]
D. [tex]r=41.5 \%[/tex]



Answer :

Certainly! To solve for the rate [tex]\( r \)[/tex] in a simple interest problem, we use the formula for simple interest:

[tex]\[ I = P \times r \times t \][/tex]

where:
- [tex]\( I \)[/tex] is the interest amount.
- [tex]\( P \)[/tex] is the principal amount.
- [tex]\( r \)[/tex] is the rate of interest per period.
- [tex]\( t \)[/tex] is the time the money is invested or borrowed for.

Given:
- [tex]\( I = \$290.50 \)[/tex]
- [tex]\( P = \$1000 \)[/tex]
- [tex]\( t = 7 \)[/tex] years

We are asked to find the rate [tex]\( r \)[/tex], to do this we rearrange the formula to solve for [tex]\( r \)[/tex]:

[tex]\[ r = \frac{I}{P \times t} \][/tex]

Plugging in the values:

[tex]\[ r = \frac{290.50}{1000 \times 7} \][/tex]

First, calculate the denominator:

[tex]\[ 1000 \times 7 = 7000 \][/tex]

Now divide the interest by this value:

[tex]\[ r = \frac{290.50}{7000} = 0.0415 \][/tex]

The rate [tex]\( r \)[/tex] is 0.0415 when expressed as a decimal. To convert this to a percentage, we multiply by 100:

[tex]\[ r_{\text{percentage}} = 0.0415 \times 100 = 4.15\% \][/tex]

Thus, the rate of interest is [tex]\( 4.15\% \)[/tex].

We compare this to the given options:
- [tex]\( 1.45 \% \)[/tex]
- [tex]\( 4.15 \% \)[/tex]
- [tex]\( 28.85 \% \)[/tex]
- [tex]\( 41.5 \% \)[/tex]

The closest match and correct answer is:

[tex]\[ r = 4.15\% \][/tex]