Question

at what rate percent per annum will be 640 amount to 774.40 in 2 year , interest being compounded annually​

Answer 1

Answer:

Amount = P ( 1 + R / 100 ) t

= 774.50 = 640 ( 1 + R /100 )^2

= 77440 / 100 = 640 ( 1+ R /100 )^2

= 7744 / 10 = 640 ( 1 + R / 100 )^2

= 7744 / 10 ÷ 640 = ( 1 + R / 100 )^2

= 7744 / 6400 = ( 1 + R /100 )^2

= ( 88/80 )2 = ( 1 + R/ 100 )^2

= ( 1 + R / 100 ) = 88 / 80

= R / 100 = 88/80 - 1

= R / 100 = 8 / 80

= R / 100 = 1 / 10

Hence , R = 10 .

Therefore the rate of interest is 10%