Answer:

X = $374.16

Step-by-step explanation:

First we have to calculate for the amount of interest using compound interest formula

A = P(1+(r/n))^(nt)

P (principal) = 1000

r (rate) = 10% = 0.1

t (time in year) = 30

n (number of recursion per year) = 1

A = 1000(1+(0.1/1))^(1*30) = 17,449.40

Amount of compound interest for 30 years is

I = A - P = 17,449.40 -1000 = 16,449.40

Amount of interest due per year

= I/30

= 16,449.40/30 = 548.313

The guy paid the same amount of interest due for the first 10 years

548.313*10 = 5483.13

And the next 10 payments equal to 150% of the interest due (150% = 1.5 times)

548.313*10*1.5 = 8224.7

Total of paid interest is

8224.7 + 5483.13 = 13707.83

So, the balance unpaid loan is

17449.40 - 13707.83 = 3741.57

This balance payment is dividend for the last 10 years, so

3741.57/10 = 374.16

So X = $374.16