let
i= Interest
p= Principle
r= rate
t= time
data given
i= $2520
p= $7000
t= 4years
r= ?
From the formula
i= prt
we make 'r' the subject by multiplying by pt both sides
i/pt=prt/pt
i/pt=r
its the same like
r=i/pt
r=$2520/($7000×4)
r=$2520/$28000
r=3/350
r=0.09%
therefore the interest rate is 0.09%
