Question

Mrs.karna has a recurring deposit account in punjab national bank for 3 years at 8% p.a. if she gets rs.9990 as interest at the time of maturity ,find the monthly installment .

Answer 1

$Let \: monthly \: instalment \: of \:Mrs.Karna = Rs \: P$

$Time (T) = 3 \: years$

$Number \: of \: months (n) = 3 \times 12 \: months \\= 36 \: months$

$Rate \:of \: interest (r) = 8\% \: p.a$

$Simple \: Interest (S.I) = Rs \: Rs\: 9990$

$\boxed { \pink { S.I = P\times \frac{n(n+1)}{2 \times 12 } \times \frac{r}{100} }}$

$\implies 9990 = P\times \frac{36(36+1)}{2\times 12} \times \frac{8}{100}$

$\implies 9990 = P\times \frac{36\times 37}{2\times 12} \times \frac{8}{100}$

$\implies 9990 = P\times 4.44$

$\implies P = \frac{9990}{4.44}$

$\implies P = Rs \: 2250$

Therefore.,

$\red{Monthly \: instalment \: of \:Mrs.Karna}\\\green {= Rs \: 2250}$

•••♪