Question

If the rates of compound interest for the first and second year are 7% and 8% respectively, let us write by calculating compound interest on Rs 6000 for 2 years.​

Answer 1

Solution :

Here, the principal being acted upon is Rs. 6000 .

The time period is 2 years .

For the first year : The rate of interest is 7%

For the second year : The rate of interest is 8%

Amount after both the years :

> P( 1 + R_1/100 )t_1 × ( 1 + R_2/100)^ t_2

> 6000( 1 + 7/100)( 1 + 8/100)

>6000 × 107 × 108/10000

> Rs. 6933.6

Compound Interest :

> Amount - Principal

> Rs.933.6 .

This is the required answer.

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Answer 2

$\Large{\bf{Given\::}}$

• Principal (P) = Rs.6000

☛ The rates of compound interest for the 1st and 2nd year are 7% and 8% respectively.

• R₁ = 7%

• R₂ = 8%

$\\ \Large{\bf{To\: Find\::}}$

• Compound Interest.

$\\ \Large{\bf{Solution\::}}$

☛ Amount (A) after 2 years is given by,

➳ $\bf{A\:=\:P\:\bigg(1\:+\:\dfrac{R_1}{100}\bigg)\:\bigg(1\:+\:\dfrac{R_2}{100}\bigg)\:}$

➳ $\tt{A\:=\:6000\:\bigg(1\:+\:\dfrac{7}{100}\bigg)\:\bigg(1\:+\:\dfrac{8}{100}\bigg)\:}$

➳ $\tt{A\:=\:6000\:\bigg(\dfrac{107}{100}\bigg)\:\bigg(\dfrac{108}{100}\bigg)\:}$

➳ $\tt{A\:=\:6000\:\bigg(\dfrac{107\times{108}}{100\times{100}}\bigg)\:}$

➳ $\tt{A\:=\:6000\:\times{\dfrac{11556}{10000}}\:}$

➳ $\tt{A\:=\:6\:\times{\dfrac{11556}{10}}\:}$

➳ $\tt{A\:=\:\dfrac{69336}{10}\:}$

➳ $\bf{Amount\:(A)\:=\:Rs.6933.6\:}$

⠀⠀

☛ As we know that,

➵ Compound Interest = Amount - Principal

⠀

➵ C.I = Rs.6933.6 - Rs.6000

⠀

➵ C.I = Rs.(6933.6 - 6000)

⠀

➵ C.I = Rs.933.6

⠀

∴ Compound Interest is Rs.933.6.