The simple interest formula is:

Where
i is the interest earned
P is the initial (loan) amount
r is the rate of interest
t is the time
Given,
P = 6500
r = 8%, or, 8/100 = 0.08
t = 5
Substituting, we get:

This is only the interest. Beyonce would need to pay the original (6500) plus this interest (2600) in total. Thus, she will have to pay:
