A sum of ₹x amount to ₹12,777.60 in 2 years at 15%p.a., when the interest is compounded eight-monthly. The value of x is _____.

₹9600

Interest is compounded 8 monthly.

So, Time = 2 years = 24 months

Rate =  \(\frac{8 }{12}\) × 15% = 10%

Now,               Principal  :  Amount

1st 8 month           10     :     11 

2nd 8 month          10     :     11

3rd 8 month           10     :     11

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overall                 1000   :     1331

ATQ,

1331R = 12777.60

1R = 9.6

Sum = 1000R = 1000 × 9.6 = Rs. 9600