P = L * (1 - t) / (1 - t^n)
t = 1/r
r = 1 + i/12
r = 1 + 0.04625/12 = 12.04625/12
t = 12 / 12.04625
P = 24000 * (1 - 12/12.04625) / (1 - (12/12.04625)^120)
P = 249.22031141994441097328847180413
So the monthly payment will be $249.22
How much will be in interest? Take the monthly payment, multiply it by the number of payments and subtract the original loan amount
249.22 * 120 - 24000 =>
5906.4373703933293167946166164954
$5906.44 will be in interest
NOTE: The windows calculator has this function. Clcik View, then click on the Worksheets.
EDIT:
Your payment of 250.18 was right. I made one small mistake
P = L * (1 - t) / (t * (1 - t^n))
t = 1/r
r = 1 + i/12
If you notice, I posted this: L * (1 - t) / (1 - t^n), instead of L * (1 - t) / (t * (1 - t^n))
P = 24000 * (1 - 1/r) / ((1/r) * (1 - (1/r)^n))
P = 24000 * (1/r) * (r - 1) / ((1/r) * (1 - (1/r)^n))
P = 24000 * (r - 1) / (1 - (1/r)^n)
P = 24000 * (1 + i/12 - 1) / (1 - (1/r)^120)
P = 2000 * i / (1 - (1/r)^(120))
P = 2000 * 0.04625 / (1 - (1/(1 + 0.04625/12))^(120))
P = 250.18084803687544672391468778921
250.18 * 120 - 24000 =>
6021.7017644250536068697625347048