Question

using the formula calculate the amount and the CI in each of the following question:​

Answer 1

Answer:

A=189.15

B=649.28

Explanation:

1200(1+5/100)³

=>1200*21/20x21/20x21/20

=>1389.15

1389.15-1200=189.15

(A)189.15

(B)2500(1+8/100)³

=>2500*108/100*108/100*108/100

=>3149.28

3149.28-2500=649.28

(B)649

=>649.28

Answer 2

Answer:

Question :-

➳ Using the formula, calculate the amount and CI in each of the following :-

(i) P = ₹ 1200; R = 5% p.a.; n = 3 years

(ii) P = ₹ 2500; R = 8% p.a.; n = 3 years

Formula Used :-

$\clubsuit$ Amount Formula :

$\bigstar \: \: \sf\boxed{\bold{\pink{A =\: P\bigg(1 + \dfrac{r}{100}\bigg)^n}}}\: \: \: \bigstar$

where,

• A = Amount
• P = Principal
• r = Rate of Interest
• n = Time Period

$\clubsuit$ Compound Interest or C.I. Formula :

$\bigstar \: \: \sf\boxed{\bold{\pink{Compound\: Interest =\: A - P}}}\: \: \: \bigstar$

where,

• A = Amount
• P = Principal

Solution :-

$\sf\bold{\purple{\underline{\bigstar\: (i)\: P =\: ₹\: 1200; R =\: 5\%\: p.a.; n =\: 3\: years}}}$

First, we have to find the amount :-

Given :

• Principal = ₹ 1200
• Time Period = 3 years
• Rate of Interest = 5% per annum

According to the question by using the formula we get,

$\implies \sf A =\: 1200\bigg(1 + \dfrac{5}{100}\bigg)^3$

$\implies \sf A =\: 1200\bigg(\dfrac{105}{100}\bigg)^3$

$\implies \sf A =\: 1200\bigg(\dfrac{105}{100} \times \dfrac{105}{100} \times \dfrac{105}{100}\bigg)$

$\implies \sf A =\: 1200\bigg(\dfrac{1157625}{1000000}\bigg)$

$\implies \sf A =\: \dfrac{1200 \times 1157625}{1000000}$

$\implies \sf A =\: \dfrac{1389150000}{1000000}$

$\implies \sf\bold{\green{A =\: ₹\: 1389.15}}$

Hence, the amount is ₹ 1389.15 .

Now, we have to find the compound interest :

Given :

• Amount = ₹ 1389.15
• Principal = ₹ 1200

According to the question by using the formula we get,

$\dashrightarrow \sf Compound\: Interest =\: 1389.15 - 1200$

$\dashrightarrow \sf\bold{\red{Compound\: Interest =\: ₹\: 189.15}}$

$\therefore$ The compound interest is ₹ 189.15 .

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$\sf\bold{\purple{\underline{\bigstar\: (ii)\: P =\: ₹\: 2500; R =\: 8\%\: p.a.;\: n =\: 3\: years}}}$

First, we have to find the amount :

Given :

• Principal = ₹ 2500
• Rate of Interest = 8% per annum
• Time Period = 3 years

According to the question by using the formula we get,

$\implies \sf A =\: 2500\bigg(1 + \dfrac{8}{100}\bigg)^3$

$\implies \sf A =\: 2500\bigg(\dfrac{108}{100}\bigg)^3$

$\implies \sf A =\: 2500\bigg(\dfrac{108}{100} \times \dfrac{108}{100} \times \dfrac{108}{100}\bigg)$

$\implies \sf A =\: 2500\bigg(\dfrac{1259712}{1000000}\bigg)$

$\implies \sf A =\: \dfrac{2500 \times 1259712}{1000000}$

$\implies \sf A =\: \dfrac{3149280000}{1000000}$

$\implies \sf\bold{\green{A =\: ₹\: 3149.28}}$

Hence, the amount is ₹ 3149.28 .

Now, we have to find the compound interest :

Given :

• Amount = ₹ 3149.28
• Principal = ₹ 2500

According to the question by using the formula we get,

$\dashrightarrow \sf Compound\: Interest =\: 3149.28 - 2500$

$\dashrightarrow \sf\bold{\red{Compound\: Interest =\: ₹\: 649.28}}$

$\therefore$ The compound interest is ₹ 649.28 .

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