To solve this problem, we need to use the formula for compound interest, which is A = P(1 + r/n)^(nt), where A is the total amount, P is the principal amount, r is the annual interest rate, n is the number of times the interest is compounded per year, and t is the time in years.
In this case, P = 150000, r = 21%, n = 2 (since the interest is compounded half-yearly), and t = 8/12 (since the loan is for 8 months).
Plugging in these values, we get:
A = 150000(1 + 0.21/2)^(2*(8/12))
= 150000(1.105)^0.67
= 150000(1.065)
= 159750
Therefore, Ram should pay RS 159750 compounded half yearly at the end of 8 months.