Question

Calculate the amount on a sum of Rs 65000 for 3 years at 10% p.a. when

the interest is compounded annually.​

Answer 1

SOLUTION:-

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ANSWER:-

• Amount = Rs. 86515
• Compund Interest = Rs. 21515

GIVEN:-

P (Principal) = Rs 65000

R (Rate) = 10% p.a (Per Annum)

T (Time) = 3 years

TO FIND:-

Compound Interest = ?

FORMULA:-

${\to{\sf{Amount (A)={P(\dfrac{1}{1} +\dfrac{R}{100} )^{n}}}}}$

${\to{\sf{Compound \: Interest \: (CI) = A - P \: (Amount - Principal)}}}$

SOLVING BY APPLYING THE FORMULA:-

• To find the compound interest first we need to find Amount.

${ \to{ \sf{A = P (\dfrac{1}{1} + \dfrac{R}{100})^{n} }}}$

${\to{\sf{A = 65000( \dfrac{1}{1}+\dfrac{10}{100})^{3}}}}$

• Take LCM.
• LCM = 100

${ \to{ \sf{A = (\frac{100 + 10}{100})^{3}}}}$

${\to{\sf{A = 65000( \dfrac{110}{100})^{3} }}}$

${\to{\sf{A = 65000( \dfrac{1331000}{1000000})}}}$

${\to{\sf{A = 65{\not{000}} \times \dfrac{1331{ \not{000}}}{1{\not{000000}}}}}}$

• Cutting the zeros of 65,000 and 1,331,000 by 1,000,000 = 65×1331/1.

${\to{\sf{A = 65 \times \dfrac{1331}{1}}}}$

${\to{\sf{A = 65 \times 1331}}}$

${\to{\sf{A = 65 \times 1331 = 86515}}}$

${\mapsto{\sf{A = 86515}}}$

Amount is Rs 86515.

• Now to find the compound interest we need to apply the formula that is Amount-Principal

${\to{\sf{CI = A - P}}}$

${\to{\sf{CI = 86515 - 65000}}}$

${\to{\sf{CI = 86515 - 65000 = 21515}}}$

${\mapsto{\sf{CI = Rs \: 21515}}}$

So compound interest is Rs. 21515.

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