Question

Compound interest is 780, rate 16.66 , time 2 years what is principle

Answer 1

Given, CI = 780

Rate = 16.66 that is equivalent to 1/6 % = 100/6

Time = 2 years.

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CI = Principal (1+r/100)^t - principal , where r is rate and t is time.

780 = P ( 1 + (100/6) / 100)² - P

780 = P ( 1 + 1/6 )² - P

780 = P ( 7/6 )² - P

780 = P (49/36 ) - P

P (49/36 ) - P = 780

49P - 36P = 780 * 36

13P = 28080

P = 28080/13

P = 2160

Hence we got our principal amount as 2160 rupees .