In what time will Rs. 390625 amount to Rs. 456976 at 4 per cent compound interest?

∵ P(1 + r/100)^t = A
⇒ 390625(1 + 4/100)^t = 456976
⇒ (1 + 4/100)^t = 456976/390625 =(26/25)⁴
⇒ (26/25)^t = (26/25)⁴
⇒ t = 4
∴ The required time is 4 years.