Li invests money in a savings account. She wants to know the amount of simple interest that she will earn in 6 years at 3 point 7 5 percent. What additional information does she need to find this amount?

Simple interest is calculated using I = P × r × t, where P is the principal, r is the interest rate, and t is the time. Li already knows the time is 6 years and the rate is 3.75%, so she needs to know the principal, or the amount she invests. The correct choice is principal.

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