Question

1) Amal Roy deposits 2000 in the bank and Poshupoti Ghosh deposits 2000 in the post office at the same time. After 3yrs. they get the return amounts 2360 and 2480 respectively. Let us write by calculating, the ratio of the rate of simple interest in percent per annum in the bank and that of in the post office.​

Answer 1

Solution :

• Amal Roy deposits 2000 in the bank and after 3 years gets back Rs. 2360

So, amount of money gained by Amal Roy :

=> Rs. 360

• Poshupoti Ghosh deposits 2000 in the bank and after 3 years gets back Rs. 2480

So, amount of money gained by Poshupoti Ghosh :

=> Rs. 480

The principal of both of them is the same , Rs . 2000

Time of deposit = 3 years .

Let the rate of interest at the post office be x% per annum and that at the bank be y% per annum

According to the formula of SI

=> x × 3 × 2000/100 = 360

=> 60x = 360

=> x = 6%

Hence the post office offers 6% interest rate .

=> x × 3 × 2000/100 = 480

=> 60x = 480

=> x = 8%

Hence the bank offers 8% interest rate .

Required ratio - 3:4

This is the answer

____________________'________________________

Answer 2

Answer:

Given :-

• Amal Roy deposits Rs 2000 in the bank and Poshupati Ghosh deposits Rs 2000 in the post office at the same time. After 3 years they get the return amount of Rs 2360 and Rs 2480 respectively.

To Find :-

• What is the ratio of the rate of the simple interest in percent per annum in the bank and that of in the post office.

Formula Used :-

$\sf\bold{\boxed{\large{R\: =\: \dfrac{S.I \times 100}{P \times T}}}}$

where,

• R = Rate of Interest
• S.I = Simple Interest
• P = Principal
• T = Time

Solution :-

$\underline{\sf{\green{✠\: In\: case\: of\: bank\: :-}}}$

Given :

• Principal = Rs 2000
• Time = 3 years
• Amount = Rs 2360
• Simple Interest = 2360 - 2000 = Rs 360

According to the question by using the formula we get,

↦ $\sf R\: =\: \dfrac{360 \times 100}{2000 \times 3}$

↦ $\sf R\: =\: \dfrac{36000}{6000}$

↦ $\sf R\: =\: \dfrac{\cancel{36000}}{\cancel{6000}}$

➠ $\sf\red{R\: =\: 6\: \%}$

Again,

$\underline{\sf{\green{✠\: In\: case\: of\: post\: office\: :-}}}$

Given :

• Principal = Rs 2000
• Time = 3 years
• Amount = Rs 2480
• Simple Interest = 2480 - 2000 = Rs 480

According to the question by using the formula we get,

⇒ $\sf R\: =\: \dfrac{480 \times 100}{2000 \times 3}$

⇒ $\sf R\: =\: \dfrac{48000}{6000}$

⇒ $\sf R\: =\: \dfrac{\cancel{48000}}{\cancel{6000}}$

➦ $\sf\red{R\: =\: 8\: \%}$

Now, we have to find the ratio of the rate of simple interest in the bank and that of in the post office and,

↪ Rate of Interest of Bank : Rate of Interest of Post office

↪ 6% : 8%

➲ 3% : 4%

$\therefore$ The ratio of the rate of simple interest in percent per annum in the bank and that of in the post office is 3% : 4% .