# A Sum of Money, Lent Out at Simple Interest, Doubles Itself in 8 Years. Find : (I) the Rate of Interest (Ii) in How Many Years Will the Sum Become Triple (Three Times) of Itself at the Same Rate - Mathematics

Sum

A sum of money, lent out at simple interest, doubles itself in 8 years. Find :
(i) the rate of interest
(ii) in how many years will the sum become triple (three times) of itself at the same rate percent?

#### Solution

Let P = Rs.100, A = Rs.200

I = Rs.200 − Rs.100 = Rs.100, T = 8 years

R =(100xx"I")/("P"xx"T")=(100xx100)/(100xx8)

=100/8=25/2%

Now again P = Rs.100

A = Rs.300

I = Rs.300 − Rs.100 = Rs.200

R = 25/2%

T =(100xx"I")/("P"xx"R")=(100xx200)/(100xx25/2)=(100xx200xx2)/(100xx25)

= 16 Years

So the given sum of money will become triple in 16 years.

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#### APPEARS IN

Selina Concise Mathematics Class 8 ICSE
Chapter 9 Interest
Exercise 9 (B) | Q 3 | Page 108