Question
A sum of money placed at compound interest doubles itself in 5 years. In how many years, it would amount to eight times of itself at the same rate of interest ?
Answer: Option D
Answer: (d)Let the Principal be P and rate of interest be r%.2 P = P$(1 + r/100)^2$2 = $(1 + r/100)^5$ ...(i)On cubing both sides,8 = $(1 + r/100)^15$Time = 15 yearsUsing Rule 5,Here, m = 2, t = 5 yearsIt becomes 8 times = $2^3$ timesin t × n = 5 × 3 = 15 years
Was this answer helpful ?
Answer: (d)Let the Principal be P and rate of interest be r%.2 P = P$(1 + r/100)^2$2 = $(1 + r/100)^5$ ...(i)On cubing both sides,8 = $(1 + r/100)^15$Time = 15 yearsUsing Rule 5,Here, m = 2, t = 5 yearsIt becomes 8 times = $2^3$ timesin t × n = 5 × 3 = 15 years
Was this answer helpful ?
More Questions on This Topic :
Latest Videos
Latest Test Papers
Submit Solution