Question

Mr Naresh kept his money in a bank which gives a simple interest of 5% p.a. becomes 16700 Rs at the end of 6 years and 18300 Rs at the end of 10 years. Find the principal and interest earned /year​

Answer 1

$\red{\textbf{principal :-400}}$

$\red{\textbf{interest :- Rs .14,300}}$

Step-by-step explanation:

$as \: we \: know \: that \: amounts \: on \: simple$

$interest \: at \: the \: end \: of \: \: every \: year \: is \: in \: AP$

$so , we \: have$

$A_{6} = 16700$

$= A + 5d \: = 16700 - - - - (1)$

$and \: A_{10} = 18300$

$A + 9d \: = 18300 - - -- - (2)$

$subtracting \: equation \: (2) \: from \: (1)$

$4d = 1600$

$d = \LARGE \frac{1600}{4}$

$d = 400$

$putting \: d = 400 \: in \: equation \: (1)we \: get$

$A + 5(400) = 16700$

$A = 16700 - 2000$

$A = 14700$

$so ,\: the \: amount \: at \: the \: end \: first \: \: year$

$= \: Rs.14700$

$interest \: earned \: per \: year \: = Rs.400$

$thus, \: principal = A - I$

$= 14700 - 400$

$= Rs. 14 300$