you deposit $1200 in an account that earns simple interest. after 42 months, the account earns $96.60 in…

Explanation:

Step1: Convert months to years

Since 1 year has 12 months, $t=\frac{42}{12}= 3.5$ years.

Step2: Use simple - interest formula

The simple - interest formula is $I = Prt$, where $I$ is the interest, $P$ is the principal amount, $r$ is the annual interest rate (in decimal form), and $t$ is the time in years. We know that $I = 96.60$, $P=1200$, and $t = 3.5$. Substitute these values into the formula: $96.60=1200\times r\times3.5$.

Step3: Solve for $r$

First, simplify the right - hand side: $1200\times3.5r = 4200r$. Then, solve for $r$: $r=\frac{96.60}{4200}=0.023$.

Step4: Convert $r$ to a percentage

To convert $r$ from a decimal to a percentage, multiply by 100. So, $r = 0.023\times100 = 2.3%$.

Answer:

B. 2.3%