so smple interest
P=principal but it should represent PRESENT amount since that makes more sens
so
1. depodid 5000, interest rate =2.5%
the deposit is the present amount or P
2.5%=interest rate in %
t=1 year
so
first you have to convert 2.5% to 0.025 (move decimal place 2 places to left)
so
I=5000 times 0.025 times 1
I=125
interest in 1 year=$125
I hope you get it
I will also do no.4
4.
borrowed 8000 for 4 years
repaid10320
so we know that interest+amount borrowed=repaid
amound borrowed=8000
repaid=10320
so
interest+8000=10320
subtract 8000
interst=2320
so
I=2320
t=4 years
P=8000
r=????
solve
2320=8000 times ??? times 4
2320=32000 times ???
divide both sides by 32000
0.0725=???
move decimal place 2 places to right ot convert to percent
7.25%
answe ir 7.25%