Question

how much compound interset of rs.40960 will be obtained in three years if rate of interest is12.5% annual


please answer it quickly​

Answer 1

Solution :

$\bf{\red{\underline{\bf{Given\::}}}}$

• Principal, (P) = Rs.40960
• Rate, (R) = 12.5% p.a.
• Time, (T) = 3 years

$\bf{\red{\underline{\bf{To\:find\::}}}}$

The compound Interest.

$\bf{\red{\underline{\bf{Explanation\::}}}}$

We know that formula of the amount :

$\boxed{\bf{A=P\bigg(1+\frac{R}{100} \bigg) ^{n} }}}}$

A/q

$\mapsto\sf{A=40960\bigg(1+\dfrac{12.5}{100} \bigg)^{3} }\\\\\\\mapsto\sf{A=40960\bigg(1+\dfrac{12.5\times 10}{100\times 10} \bigg)^{3} }\\\\\\\mapsto\sf{A=40960\bigg(1+\cancel{\dfrac{125}{1000}} \bigg)^{3} }\\\\\\\mapsto\sf{A=40960\bigg(1+\dfrac{1}{8} \bigg)^{3} }\\\\\\\mapsto\sf{A=40960\bigg(\dfrac{8+1}{8}\bigg)^{3} }\\\\\\\mapsto\sf{A=40960\times \bigg(\dfrac{9}{8} \bigg)^{3} }\\\\\\\mapsto\sf{A=\cancel{40960} \times \dfrac{729}{\cancel{512}} }\\\\\\\mapsto\sf{A=Rs.(80\times 729)}$

$\mapsto\sf{\orange{A=Rs.58320}}$

Now;

$\boxed{\mid\bf{Compound\:Interest\:\mid}}}}$

$\longrightarrow\sf{C.I.=Amount-Principal}\\\\\longrightarrow\sf{C.I.=Rs.58320-Rs.40960}\\\\\longrightarrow\sf{\orange{C.I.=Rs.17360}}$

Answer 2

Given:

◕Principal(p) =Rs.40960

◕Rate(R) = 12.5%

◕Time(T) = 3 years

◕Compound interest (CI) = ?

✧Ist Formula,

☞ A= P(1+R/100)^t

☞ Amount = 40960(1+12.5/100)³

→ 40960(1+125/1000)³

→40960(1+1/8)³

→40960(9/8)³

→40960×9/8×9/8×9/8

→58320Rs

✿ Compound interest = Amount-Principal

→C.I = A - P

→C.I = 58320-40960

→C.I = Rs.17360

✧2nd formula,

☞C.I = P [(1+R/100)^t-1]

→40960[(9/8)×(9/8)×(9/8)-1]

→40960[(729/512)-(1/1)]

→40960[217/512]

→40960[0.4238]

→17360Rs