A sum of $\rupee 2000$ is invested at $7\%$ per annum simple interest. Calculate the interest at the end of $1^{st}$, $2^{nd}$ and $3^{rd}$ year. Do these interests form an AP? If so, find the interes

Question

A sum of $\rupee 2000$ is invested at $7\%$ per annum simple interest. Calculate the interest at the end of $1^{st}$, $2^{nd}$ and $3^{rd}$ year. Do these interests form an AP? If so, find the interest at the end of the $27^{th}$ year.

Accepted Answer

Step 1: Interest at the end of $1^{st}$ year $= \frac{2000 	imes 7 	imes 1}{100} = upee 140$
Interest at the end of $2^{nd}$ year $= \frac{2000 	imes 7 	imes 2}{100} = upee 280$
Interest at the end of $3^{rd}$ year $= \frac{2000 	imes 7 	imes 3}{100} = upee 420$
Step 2: $140, 280, 420$. Yes, interests form an AP with first term $= 140$ and common difference $= 140$.
Step 3: Interest at the end of $27^{th}$ year $= 140 + 26 	imes 140 = 140 + 3640 = upee 3780$

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