problem:
Frank dediced to buy a new bike with loan.
The interest rate is 9%, the loan $ 7 600,- the interest € 399,-
What is the time (months)?
answer:
1. step: given/wanted
capital: $ 7 600,-
interest: $ 399,-
interest rate: 9%
wanted: time (months) ?
2. step: calculate
i = interest c = capital ir = interest rate d = days
i = c * ir * m / * 1 200
1 200
i * 1 200 = c * ir * m / : (c * ir)
m = i * 1 200
(c + ir)
m = 399 * 1 200
(7 600 * 9)
m = 7 months
3. step: answer
He has to pay back the loan within 7 months.