If a certain sum of money doubles itself in 6 years, in how many years will it…
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If a certain sum of money doubles itself in 6 years, in how many years will it be three times at the same rate of simple interest?
- A.
10 years
- B.
19 years
- C.
12 years
- D.
33 years
Attempted by 6 students.
Show answer & explanation
Correct answer: C
Step-by-Step Solution
To find the time required for a sum to triple itself under simple interest, we can analyze the growth of the interest earned.
Analyze the first scenario (doubling):
If a sum doubles, the Amount (A) becomes 2P (where P is the principal).
Simple Interest (SI) earned = Amount - Principal = 2P - P = P.
This interest (P) is earned in 6 years.
Analyze the second scenario (tripling):
To triple the sum, the Amount (A) must become 3P.
Simple Interest (SI) required = Amount - Principal = 3P - P = 2P.
Calculate the time required:
Since Simple Interest is directly proportional to time, we can set up a ratio:
(SI 1) / (Time 1) = (SI 2) / (Time 2)
P / 6 years = 2P / (Time 2)
Time 2 = (2P * 6 years) / P
Time 2 = 12 years.