Question

A sum of money amounted to ₹31200 at 4% per annum in 5 years. Find the original sum

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Answer 1

$\sf{\underline{\boxed{\large{\blue{\mathsf{Solution}}}}}}$

$\sf{\bold{\green{\underline{\underline{Given}}}}}$

• Amount = Rs. 31200
• Rate = 4%
• Time = 5 years

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$\sf{\bold{\green{\underline{\underline{To\:Find}}}}}$

• principle = ???

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$\sf{\bold{\green{\underline{\underline{Solution}}}}}$

$\sf{\red{\boxed{\bold{Interest = \dfrac{p\times r \times t }{100}}}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ interest = \dfrac{ p \times 4 \times 5 }{100}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ interest = \dfrac{ p \times 4 }{20}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ interest = \dfrac{ p }{5}}}$

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$\sf{\red{\boxed{\bold{Amount = principle + interest}}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{31200 = p + \dfrac{ p }{5}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ 31200 = \dfrac{ 5p + p }{5}}}$

⠀⠀

: $\sf\implies\:{\bold{ 31200 = \dfrac{ 6p }{5}}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ p = \dfrac{31200\times 5 }{ 6 }}}$

⠀⠀⠀⠀

: $\sf\implies\:{\bold{ p = 5200 \times 5}}$⠀⠀⠀⠀

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: $\sf\implies\:{\bold{ p = Rs. 26000}}$

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$\sf{\bold{\green{\underline{\underline{Answer}}}}}$

• Rs. 26000 will amount to Rs.31200 in 5 years at the rate of 4% per annum .