Question

how long must a sum of rs 14400 be invested at 12% p.a so as to earn an interest of rs 7200?

Answer 1

Hari Om...!

we have,

principle = Rs 14400

rate = 12℅ per annum.

simple interest = Rs 7200.

we know,

time = $\frac{simple \: interest \times 100}{principle \times rate}$

= $\frac{7200 \times 100}{14400 \times 12}$

= $\frac{100}{24 } = \frac{25}{6} years$

we know, 1 year = 12 months

$\frac{25}{6} \times 12 = 50months$

Thanks

KSHITIJ

Answer 2

$\huge\bold\red{Solution :\longrightarrow}$

$\mathsf{Given,}$

$\mathsf\blue{Principal \: (P)= Rs \: \: 14400}$

$\mathsf\blue{Rate \: (R) = 12\% \: \: p.a.}$

$\mathsf\blue{Interest \: (I) = 7200}$

$\mathsf\purple{Let \: \: the \: \: time \: \: be \: \: T \: \: years.}$

$\mathsf\green{We \: \: know \: \: that}$

$\mathsf\green{I = \frac{P \times R \times T}{100}}$

$\mathsf\green{= > 7200 = \frac{14400 \times 12 \times T}{100}}$

$\mathsf\green{ = > 7200 = 144 \times 12T}$

$\mathsf\green{ = > 7200 = 1728T}$

$\mathsf\green{ = > T = \frac{7200}{1728}}$

$\mathsf\green{ = > T = \frac{25}{6}}$

$\mathsf\green{= > T = \frac{25}{6} \times 12 \: \: months}$

$\mathsf\green{= > T = 50 \: \: months}$

$\mathsf\purple{= > T = 4 \: \: years \: \: 2 \: \: months}$

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