Question

in what time will a sum of money double itself at 6 whole1/4 p.a. simple interest

Answer 1

Suppose,

sum = x.

Then S.I. = x &

Rate = 6 whole 1/4 =25/4 %

Therefore time = (100*x) / (x* 25/4) = 16 years

Answer 2

P = Principal Amount = P

Amount inclusive of Interest = 2P

R = Rate of interest = 6 1/4% = 6.25%

T = Time = ?

We know that

A = P(1 + TR)

2P = P(1 + T×6.25/100)

cancel 'P' on both sides

2 = 1 + T×0.0625

2 - 1 = T × 0.0625

1/0.0625 = T = 16 years