Question

(17) Acertain sum of money doubles itself in 6 years. In how many years will it be four times at the same
rate of simple interest?​

Answer 1

Answer:

12 years

Step-by-step explanation:

The sum of money doubles in 6 years means the interest for 6 years equals to original sum of money I.e. Principle. Let the Principle = P and rate of interest = r %

So, P + P * r *6/100 = 2P

Or, p*r*6/100 = 2P - P = P

Or, r = 100/6 = 16.67 %

For sum to be treble, the interest should be twice the Principle I.e. P * (16.67/1t00) * t = 2P where t is the period when the sum will be 3 times.

Or, t = 100 * 2/16.67 = 12 years. Ans.

Simply you can also give a statement that when sum is doubled in 6 years for simple interest, the sum will be tripled in 6 * 2 = 12 years