What equation can Janet use to calculate the principal amount? (and please don't just answer try to solve it someone ripped me off, the last time i asked by just typing)

Answer:
t = [tex]\frac{l}{pr}[/tex]
Step-by-step explanation:
Formula or literal equation used to calculate the simple interest is,
l = prt
where 'l' = Simple interest
p = principle amount invested
r = rate of interest
t = time or duration of the investment
If we have to calculate the time of investment form the given formula,
l = prt
By the division property of equality,
[tex]\frac{l}{pr}=\frac{prt}{pr}[/tex]
[tex]t=\frac{l}{pr}[/tex]
Therefore, formula to be used is, [tex]t=\frac{l}{pr}[/tex]