Question

6) An amount is borrowed at simple interest for
25 years. At the end of this period, this
amount, along with its interest, has trebled
itself. What was the rate per cent?​

Answer 1

Answer:

8%

Step-by-step explanation:

$simple \: interest \: = \frac{pnr}{100 } \\ where \: p \: - \: principal \: amount \\ n \: - \: no. \: of \: years \\ r \: - \: rate \: of \: interest \\ by \: the \: given \: data \: s.i. = \frac{p \times 25 \times r}{100} \\ \\ = \frac{pr}{4} \\ also \: given \: p \: + \frac{pr}{4} = 3p \\ \frac{r}{4} = 3 - 1 \\ r = 8$

hence, rate of interest = 8%