Question

$400 is interest is earned on principal of $2000 at a simple interest rate of 5% interest per year.for how many years was the principal invested?

Answer 1

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

• Principle = Rs. 2000
• Interest = Rs. 400
• Rate = 5%

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

• Time = ??

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

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

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$: \implies\: \sf{\bold{ 400 = \dfrac{2000\times 5\times t}{100}}}$

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$: \implies\: \sf{\bold{ 400 = \dfrac{200\times 5\times t}{10}}}$

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$: \implies\: \sf{\bold{ 400 = {20\times 5\times t}}}$

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$: \implies\: \sf{\bold{ t = \dfrac{400}{20\times 5}}}$

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$: \implies\: \sf{\bold{ t = \dfrac{40}{2\times 5}}}$

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$: \implies\: \sf{\bold{ t = \dfrac{20}{5}}}$

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$: \implies\: \sf{\bold{ t = 4 years}}$

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

• In 4 years Rs. 2000 will earn Rs. 400 as simple interest at 5% per annum