what is the rate of this

The formula for compound interest is $A = P(1 + {r\over n})^{nt}$, where A is the end goal amount, P is the principal, r is the interest rate, n is the number of times applied, and t is the time.

So plugging in the values:

$A = 36000(1 + 4860)^{1.5}$

Well, I have to admit, but you'll get a lot of money. A = 12200873726 (what that's like $12.2b)

Remember, it is "simple interest rate" he/she is looking for ! The formula you used is for "compound interest"

[36,000  x  1.5 years  x  R (simple interest rate)] ==4,860

[54,000R] ==4,860, solve for R

R ==4,860 /54,000==0.09  x  100 ==9% simple interest rate