Question

What time will a sum of money double itself at 15% per annum

Answer 1

Let

principal = P

Amount = 2p

SI = A - P

= P

R = 15%

T = 100×SI/P×15

= 100×P/P×15

= 20/3 years

Answer 2

ANSWER:-

Let the principal = Rs p

Amount = A = 2p

Time = T years

Rate of interest = r = 15%

A = p( 1 + Tr/100 )

2p = p ( 1 + T × 15 /100 )

2p/p = ( 100 + 15T )/100

200 = 100 + 15T

200 - 100 = 15T

100 = 15T

100 / 15 = T

20 / 3 = T.

Hope it will help you