Question

At compound interest a certain sum becomes twice in 5 years. In how many years will it become 16times​

Answer 1

Step-by-step explanation:

Given At compound interest a certain sum becomes twice in 5 years. In how many years will it become 16 times

• Let Principal = Rs 100
• Amount = Rs 200
• Time = 5 years
• Now A = P (1 + r/100)^n
•     200 = 100 (1 + r/100)^5
•      2 = [(1 + (r/100)]^5 -------------1
•     Now if sum becomes 16 times in n years, then
•  16 = (1 + r/100)^n
• 2^4 = (1 + r/100)^n------------------2
• From 1 and 2 we get
• [(1 + r/100)^5]^4 = (1 + r/100)^n
• (1 + r/100)^20 = (1 + r/100)^n

Therefore n = 20 years.

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