#### Answer

Rate of interest is 20%.

#### Work Step by Step

Given:
Amount (A) = 4320
Principal (P) = 3000
Time (t) = 2
We have to find the rate of interest i.e.$ r$.
Step-1: Substitute the given values in the formula.
$A=P(1+r)^t$
$4320=3000(1+r)^2$
Step-2: We now solve the equation for r.
$4320=3000(1+r)^2$
Step-3: Divide both sides of the equation by 3000.
$\frac{4320}{3000}=(1+r)^2$
Step-4: Use the square root property.
$±\sqrt \frac{4320}{3000}=1+r$
Step-5: Simplify the left hand side by dividing the numerator and denominator by the Highest Common Factor(H.C.F) of 4320 and 3000
H.C.F of 4320 and 3000 is 120.
$±\sqrt\frac{4320\div120}{3000\div120} =1+r$
$±\sqrt \frac{36}{25}=1+r$
$\frac{6}{5}=1+r$
Step-6: Subtract both the sides with 1 and further simplify the left hand side.
$±\frac{6}{5}-1=r$
$\frac{±6-5}{5}=r$
Therefore, $r=\frac{1}{5}, \frac{-11}{5}$
Rate of Interest cannot be negative, hence, $r=\frac{1}{5}=0.2=20$%.