The simple interest formula is I=Prt , where I is the interest, P is the principal, r is the interest rate, and t is the time. How long would it take to have $1335.60 in interest if the principal is $5300 and the interest rate is 7.2%?

Question

Josephine Medina

Mathematics

2 November, 12:31

The simple interest formula is I=Prt , where I is the interest, P is the principal, r is the interest rate, and t is the time. How long would it take to have $1335.60 in interest if the principal is $5300 and the interest rate is 7.2%?

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Answers (1)

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Salvador Benitez · Answer 1

t = 5.3 years

(about 5 years 4 months)

Equation:

t = (1/r) (A/P - 1)

Calculation:

First, converting R percent to r a decimal

r = R/100 = 7.2%/100 = 0.072 per year,

then, solving our equation

t = (1/0.072) ((4835.6/3500) - 1) = 5.3

t = 5.3 years