Verified Answer :

We must find fixed payment amount, every period in case we know FV ( future value ) = 12000 and Interest = 10%
We use f
ormula :

FV= 
A × \(\frac{(1+i)^{n} -1 }{i}\)

A = fixed payment amount, every period   -----> finding
FV = 12000
i = 0.12
n = t
enure years = 18-12 = 6

and we found A = 
1478.7